Overview of S-type asteroid Itokawa, based on the studies on samples returned by Hayabusa.
T. Yada1, M. Abe1, T. Okada1, M. Nishimura1, R. Kanemaru1, H. Soejima1,2, K. Kumagai1,2, K. Sakamoto1, T. Usui1, and M.
Fujimoto1
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210, Japan,
2
Marine Works Japan Inc., Yokosuka, Kanagawa 237-0063, Japan.
Introduction: Hayabusa spacecraft, which was launched in May 2003, reached near-Earth S-type asteroid 25143 Itokawa in
September 2005. It landed onto the surface of the smooth terrain called “MUSES-Sea” of Itokawa twice in November 2005,
even though its touchdown sampling system had not fully functioned [1]. Hayabusa spacecraft had overcome a series oftroubles happened after the 2nd sampling and during its returning cruise back to Earth, and return its reentry capsule including
its sample container to the Woomera prohibited area in South Australia in June 2010. After a series of procedures in the
curation facility in JAXA, sub-mm sized mineral grains were recovered from its sample canister [2, 3]. A series of preliminary
examination analyses on those grains revealed that they originated from surface regolith of asteroid Itokawa and that werecomparable to equilibrated LL chondrites [4-9].
Initial descriptions and distributions of Itokawa samples: The sample canister is separated into two rooms, room A and B,
and those from the 1st touchdown should be recovered into the room A and those from the 2nd one should be in the room B,
even though the gap of the division plate between the two rooms sizes around 0.5mm and those smaller than the size of gap
might be mixed up between the two rooms. The sample container was introduced into the clean chamber and opened in static
vacuum condition in order to recover gas sample in the container even though it did not contain detectable amount of sample
gas. The sample canister was extracted from the container in purified nitrogen condition and samples grains inside the sample
canister were recovered onto quartz glass or aluminum plates due to compulsive fall by tapping the canister in upside downorientation. Individual sample grains were handpicked and handled with an electrostatically controlled micro-manipulation
system developed for Hayabusa returned samples and installed in the clean chamber of purified nitrogen condition [10]. They
were transferred to the sample chamber of the field emission secondary electron microscope equipped with the energy
dispersive X-ray spectrometer (FE-SEM/EDS) Hitachi S-4300SE/N or SU6600 without exposing to the air and examined fortheir backscattered electron images and qualitative chemical composition. After sent back to the clean chamber, they wereplaced onto gridded quartz glass slides, lately individual quartz glass containers, to be stored in its purified nitrogen condition
and given individual identification numbers. So far, 1344 of individual Hayabusa grains have been described and given sample
IDs. The sample IDs start from “RA” are from room A, which comprise 605 grains, “RB” from room B, 404 grains, “RC”
from a rotation cylinder situated between the two rooms, 86 grains, and “RX” are from both rooms, 249 grains [11]. All the
initial description information of Hayabusa sample grains are also published on the sample catalog website(https://curation.isas.jaxa.jp/curation/hayabusa/index.html). Among them, 20 of grains and one Teflon spatula containing fine
Itokawa grains have been distributed to NASA, based on Memorandum of Understanding between JAXA and NASA for the
Hayabusa mission. On the other hand, international announcement of opportunity of Hayabusa samples have been conductedsince 2012, and 254 of individual Hayabusa grains have been distributed to 69 of research plans of AO so far, which result invarious kind of scientific achievements mentioned below.
Equilibrated chondritic body Itokawa: Modal abundance, average fayalite content in olivine and ferrosilite content in lowCa pyroxene, and oxygen isotopic compositions of Itokawa grains match those of LL chondrites [4, 5, 12, 13], and distributionof fayalite contents in olivine and petrologic observation indicated its petrologic type ranges from type 4 to type 6 [4]. Olivinespinel geothermometer and plagioclase geothermometer have been applied for Itokawa mineral grains, indicating that peaktemperature they experienced during thermal metamorphism in asteroid should have reached 800˚C and it slowly cooled down
to 600˚C, which corresponds to petrologic type <5 [4, 14, 15]. The thermal metamorphism it experienced should have occurredin a body predate asteroid Itokawa. Assuming 26Al as a heat source of such body, the size of the precursor body of asteroid
Itokawa should have sized 20km in radius based on numerical simulation [16]. Concerning about its shock stage, detailed
studies on olivine and plagioclase in Itokawa grains indicate they experienced shock stage 2, moderately shocked, whichcorresponds to 5-10 GPa in shock pressure. Thus, Itokawa is an LL chondritic breccia body of various petrologic type ranging
from type 4 to 6. The U-Pb chronology obtained from phosphates found in Itokawa grains show a single isochron age of 4.64 ±0.18 Ga, indicating the precursor body should have formed in the early solar system [17]. Also a lower intersection age of the
U-Pb system is 1.51 ± 0.85 Ga, indicating catastrophic break-up event should have occurred for the precursor body of Itokawa
at this age. This age is consistent with a result of complete degas age estimated from 40Ar-39Ar system as 1.3 ± 0.3 Ga [18],whereas it is inconsistent with the degas age by 40Ar-39Ar system as 2.3 ± 0.1 Ga [19]. It seems that further confirmation isneeded for the chronological study.
What happens on asteroid Itokawa: Because Itokawa samples are the only surface regolith sample of the S-type asteroid
among all kinds of planetary samples, a series of studies for space weathering have been conducted for these samples. Surfaceof Itokawa grains shows thin (30-60 nm) amorphous layer, containing ~2nm of nano phase Fe particles [7]. The very surface of
the amorphous layers are enriched in not only Fe but also S, redeposition of nano phase FeS after micrometeoroids impact
should occur and this must redden reflectance spectrum of the asteroid effectively. Solar flare tracks are recognized in olivine
in Itokawa grains just below the amorphous phase and its track densities indicate their short surface exposure time on the orderof 103 to 104 years [20]. The fact that the exposure ages of Itokawa grains much shorter than that of Lunar regolith (>several
tens million years) are consistent with the result of exposure age estimated from cosmogenic 21Ne concentrations of Itokawa
grains as 3 million years, which is much shorter than Lunar regolith as ~400 million years [9]. Short exposure time of Itokawa
grains also pointed from little cosmogenic 10B contribution in B isotopic composition observed in Itokawa grains [21]. The
short exposure time of Itokawa regolith also indicates that large surface mass loss rate such as several tens of cm per million
years, further implied the lifetime of Itokawa as 100 to 1000 million years [9]. Different from silicate minerals, space
weathering on the surface of sulfides cause ~1 µm to several hundreds nm of iron whiskers on their surfaces caused by loss of
sulfur from sulfide surfaces and deposition onto them due to long exposure to the energetic ions of the solar wind [22]. As
mentioned before, surfaces of Itokawa grains also experienced micrometeoroids impact. Microimpact craters are reported on
the surfaces of Itokawa grains [23], which results in melt splashes and adhering particles [24] and even secondary
submicrometer craters distributed on their surfaces, assuming their exposure time as 102 to 104 years [25, 26].
New insights of S-type asteroid: Itokawa samples bring us new insights of S-type asteroid. For example, ~1 mole%enrichment of water and hydroxyl on the surface of olivine in Itokawa samples, which is caused by continuous exposure ofsolar wind to the asteroid surface, indicating ubiquitous presence of such water on airless bodies. They further assume a partof potential sources of Earth’s ocean in the early solar system [27]. Concerning about water, euhedral NaCl crystals and KCl,
which should have formed by water-rock interaction in Itokawa or its precursor body, were discovered on the surface andinterior of Itokawa grains and nanoscale NaCl grains were discovered in an Itokawa grain, indicating S-type asteroid might
have once contained certain amount of water and provided water to ancient Earth [28, 29, 30]. S-type asteroids are thought tobe poor in organic matters as ordinary chondrites, but indigenous organic matters were discovered from carbon-rich Hayabusa
grains [30, 31]. They discovered nanocrystalline graphite and disordered polyaromatic hydrocarbon in carbon-rich grains
recovered from the Hayabusa sample canister, showing D- and 15N-enrich isotopic compositions. In another report, they
discovered non-protein amino acids, racemic β-aminoisobutyric acid and β-amino-n-butyric acid in carbon-rich grains,
indicating their non-biological, non-terrestrial origins.
Concluding remarks: As mentioned above, Itokawa samples continue providing new and striking scientific results. Even
though we have (will have) other new returned asteroid samples like Ryugu from C-type asteroid [32] and Bennu from B-type
asteroid [33], Itokawa samples remain important because they are still the only S-type asteroid samples for human being.
References:[1] Kawaguchi J. et al. 2008. Acta Astronautica 62: 639. [2] Abe M. et al. 2011. Abstract #1638. 42nd LPSC. [3] Yada T. et al.
2014. Meteoritics & Planetary Science 49:135. [4] Nakamura T. et al. 2011. Science 333: 1113. [5] Yurimoto H. et al. (2011)
Science 333: 1116. [6] Ebihara M. et al. (2011) Science 333: 1119. [7] Noguchi T. et al. (2011) 333: 1121. [8] Tsuchiyama etal. (2011) Science 333: 1125. [9] Nagao K. et al. (2011) Science 333: 1128. [10] Yada T. et al. (2022) JAXA Repository,
JAXA-RR-21-009E. [11] Kanemaru R. et al. (2023) JAXA Repository, JAXA-SP-22-005E. [12] Nakashima D. et al. (2013)
Earth Planet. Sci. Lett. 379: 127. [13] Tsuchiyama A. et al. (2014) Meteoritics Planet. Sci. 49: 172. [14] Tanaka M. et al.
(2014) Meteoritics Planet. Sci. 49: 237. [15] Mikouchi T. et al. (2014) Earth Planets Space 66: 82. [16] Wakita S. et al. (2014)
Meteoritics Planet. Sci. 49: 228. [17] Terada K. et al. (2018) Scientific Reports 8: 11806. [18] Park J. et al. (2015) Meteoritics
Planet. Sci. 50: 2087. [19] Jourdan F. et al. (2017) Geology 45: 819. [20] Keller L. P. and Berger E. L. (2014) Earth Planets
Space 66: 71. [21] Fujiya W. et al. (2016) Meteoritics Planet. Sci. 51: 1721. [22] Matsumoto T. et al. (2020) Nat. Comm. 11:1117. [23]Nakamura E. et al. (2012) Proc. Nation. Acadm. Sci. 109: E624. [24] Dobrica E. and Ogliore R. C. (2016) Earth
Planets Space 68: 21. [25] Harries D. et al. (2016) Earth Planet. Sci. Lett. 450: 337. [26] Matsumoto T. et al. (2018) Icarus 303:
22. [27] Daly L. et al. (2021) Nat. Astron. https://doi.org/10.1038/s41550-021-01487-w. [28] Noguchi T. et al. (2014)
Meteoritics Planet. Sci. doi: 10.1111/maps.12333. [29] Che S. and Zega T. J. (2023) Nat. Astron.
https://doi.org/10.1038/s41550-023-02012-x. [30] Chan Q. H. S. et al. (2021) Scientific Reports 11: 5125. [31] Parker E. T. etal. (2022) Meteoritics Planet. Sci. 57: 776. [32] Yada T. et al. (2022) Nat. Astron. 6: 214. [33] Lauretta D. et al. (2022) Science
10.1126/science.abm1018.

Summary of Hayabusa2 and Status of JAXA curation
Tomohiro Usui1
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan
Japan Aerospace Exploration Agency (JAXA) has a strategic small-body sample return program tounderstand the formation, evolution, and migration of planetary building blocks, water, and organics in theearly solar system. The JAXA's sample return program started with Hayabusa for S-type asteroid Itokawa
in 2010, followed by Hayabusa-2 for C-type asteroid Ryugu in 2020, and the future mission of MartianMoons eXploration (MMX) for Phobos in 2029. My presentation covers the recent achievement of
Hayabusa 2 curation and sample analysis. I also present an overview of MMX, particularly how we leverage
the Hayabusa 2 experience to develop the MMX curation and sample science.
Hayabusa 2 team has completed the initial curation and sample analysis of the Ryugu samples. The
Hayabusa 2 curation/sample analysis is unique in having a role as a "bridge" between the remote sensing
and the sample analysis communities. Along with the conventional curation tools (e.g., optical microscopeand balance), JAXA installed remote sensing instruments (e.g., ONC: Optical Navigation Camera) in the
curation facility for ground truthing. Moreover, a flight spare of MicrOmega (infrared hyperspectral
microscope) detected important minor phases (clays, carbonates, organics) in the apparently black Ryugu
samples in the early stage of the curation. Following the initial sample analysis/curation activity, Ryugu
samples are now publicly available <https://jaxa-ryugu-sample-ao.net/>.
JAXA plans a Phobos sample return mission MMX in 2024-2029. The MMX spacecraft is scheduled tobe launched in 2024, orbit Phobos and Deimos (multiple flybys), and retrieve and return >10 g of Phobos
regolith to Earth in 2029. The Phobos regolith represents a mixture of endogenous Phobos building blocks
and exogenous materials that contain solar system projectiles (e.g., interplanetary dust particles and coarser
materials) and ejecta from Mars and Deimos. The MMX Sample Analysis Working team started designing
the curation and sample analysis protocol to identify Phobos' fragments with different origins. Under thecondition that remote sensing observations guarantee the representativeness of the sampling sites in thegeologic context of Phobos, laboratory analysis of the returned sample will provide crucial information
about the moon's origin: the capture of an asteroid or in-situ formation by a giant impact.

Future perspective of sampling and curation for extraterrestrial materials
in JAXA's small body exploration
Ryota Fukai1
1ISAS/JAXA
Introduction
Japan Aerospace Exploration Agency (JAXA) successfully completed the sample return planetary exploration missions for thesmall bodies Itokawa (Hayabusa; 2003–2010) and Ryugu (Hayabusa2; 2014–2020). JAXA is preparing to receive the next
return samples to Institute of Space and Astronautical Science (ISAS) and planning new missions for the next decade. I
introduce the concept and tentative plan for the curation of the Bennu sample returned by Origins, Spectral Interpretation,
Resource Identification, Security, Regolith Explorer (OSIRIS-REx; NASA), the Phobos sample collected by Martian Moon
Exploration (MMX; JAXA), and the comet sample collected by Next-Generation Small Body Sample Return (NGSR; JAXA).
The concept of curation in the future is threefold: ground truthing of remote-sensing and in-situ data, certification for the
curation data, and in-house contamination control. Subsequently, I introduce the scientific scopes and the key techniques forsampling the comet materials in the NGSR mission.
Curation
Ground truthing of remote-sensing and in-situ data. Ground truthing for remote-sensing and in-situ analysis data obtainedby the mission instruments should be done to complete the mission objectives in the sample return mission. The curation phaseof the return samples is the chance for ground truthing without any sample biases. In the MMX curation, the initial description
will be done with the ToF-type mass spectrometer, visible/infrared spectral imager, and Raman spectrometer, corresponding to
the mission instruments in the MMX spacecraft [1]. In addition, the simulator of Optical RadiOmeter composed of CHromatic
Imagers (OROCHI), an optical camera of the MMX spacecraft, will be installed in the Bennu clean chamber to help plan the
MMX's curation strategy [2].
Certification for the curation data. Whereas the observation in the clean chamber is useful to characterize the bulk-scale
return sample, the analytical method is limited to a totally non-destructive way. For instance, we estimated the bulk density of
Ryugu grains with the information from the weight and optical image [3]. To confirm the accuracy of the curation data within
the clean chamber, we will conduct the coordinated analysis for the return sample (e.g., Ryugu, Bennu) outside the cleanchamber, such as X-ray Computed Tomography (XCT) and Scanning Electron Microscope- Energy Dispersive Spectroscopy(SEM-EDS). This dataset is available as additional information for outreach and allocation in the Announcement ofOpportunity (AO).
In-house contamination control. Regular monitoring for the contamination of clean environments is essential to maintaincleanliness levels. We newly introduce the method for sampling the metal particles within clean rooms and chambers by Gas
Exchange Device- Inductively Coupled Plasma- Mass Spectrometer (GED-ICP-MS). We can count the number of metal
particles without any biases in the sample preparation. We can attain the cross-check for possible contamination in the returnsamples by mass spectrometric techniques developed with in-house contamination control.
Next-generation sample return mission
Scientific scopes. Following small-body explorations such as the Hayabusa and Hayabusa2 missions, we should explore moreprimitive targets in the Solar System. Our target for the next sample return is a comet, which potentially possesses the recordof the early Solar System and "presolar" system in the Milky Way Galaxy, avoiding the secondary alteration within the parent
body. Kurokawa et al. [4] will report the scientific concept of NGSR in detail.
Subsurface sampling. The surface of a comet should have non-primitive layers such as recondensed and/or consolidated
surfaces up to ~1 m depth [5]. Therefore, subsurface sampling for the comet is critical to attain the scientific objectives in
NGSR. We are developing the subsurface sampling system using a Small Carry-on Impactor (SCI) and bullet-system sampler.
References: [1] Fukai, R. et al. in revision. [2] Fukai, R. et al. (2023) METSOC. [3] Yada, T. et al. (2021) Nature Astronomy,
6, 214–220. [4] Kurokawa, H. et al. (2023) this symposium. [5] El-Maarry, M. R. et al. (2019) Space Science Review, 215 (36).

Updates on OSIRIS-REx: Return journey to Earth and the sample from Bennu
Shogo Tachibana1, Harold C. Connolly, Jr.2,3,4, Dante S. Lauretta4, and the OSIRIS-REx Sample Analysis Team1
UTOPS, University of Tokyo / ISAS, JAXA
2
Department of Geology, School of Earth & Environment, Rowan University
3
Department of Earth and Planetary Science, American Museum of Natural History
4
Lunar and Planetary Laboratory, University of Arizona
NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security and Regolith–Explorer) spacecraft
explored B-type near-Earth asteroid (101955) Bennu from December 2018 to May 2021. [1]. The spacecraft data indicated that
Bennu’s surface material contains hydrous silicates, carbonates, magnetite, and organic matter [2-4], suggesting that it
experienced aqueous alteration within a parent body. In October 2020, the spacecraft collected a sample of surface material
from a site nicknamed Nightingale within the 20-m-diameter Hokioi crater. The in-flight inspection of the sample with the
SamCam imager showed that millimeter- to centimeter-sized particles were successfully collected [5]. Analysis of various
telemetry data from before and after sample collection yielded an estimated sample mass of 250 ± 101 g, well above themission goal (60 g) [5]. The spacecraft will fly by Earth and drop the Sample Return Capsule (SRC) into the Utah desert in thewestern United States on September 24, 2023. As of writing (September 21, 2023), the spacecraft is on track targeting Earth.
After retrieval, the SRC will be delivered to the NASA Johnson Space Center (JSC) to be curated in a new cleanroom
dedicated to the Bennu sample [6]. At the symposium, we will report updates on the SRC retrieval operation, curation
processes at JSC, and the sample.

References[1] Lauretta D. S. et al. 2019. Nature 568: 55-60. [2] Hamilton V. E. et al. 2019. Nat. Astron. 3:332-340. [3] Kaplan H. H. et al.
2020. Science 370:eabc3557. [4] Simon A. A. et al. 2020. Science 370:eabc3522. [5] Lauretta D. S. et al. 2022. Science
377:285-291. [6] Righter K. et al. 2023. Meteorit. Planet. Sci. 58: 572-590.

Developing European Curation for MMX Samples
1

Aurore Hutzler , Aliz Zemeny2, Jörn Helbert3, Jean Duprat4, Elliot Sefton-Nash1, Enrica Bonato3, 5 and Kamini Manick2
1
ESTEC, European Space Agency, The Netherlands
2
ECSAT, European Space Agency, United Kingdom
3
Institute for Planetary Research, German Aerospace Center (DLR), Germany
4

Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), France
5

Museum für Naturkunde Berlin, Germany

Curation of extraterrestrial samples is imperative for maximizing science return. Despite Europe's established meteorite andoverall museal curation expertise, it currently lacks specialized infrastructure for samples directly returned from space. An
opportunity to enhance capabilities in this area is provided by the Martian Moon eXploration (MMX) mission. MMX is led by
the Japan Aerospace Exploration Agency (JAXA) and is planned to return >10g of core and regolith material from Phobos to
Earth in July 2029 [1, 2].
Cooperative discussions between partnering space agencies and European institutions regard possible transfer of a portion of the
anticipated MMX sample collection for long-term curation in European institutions, following the period of initial description at
JAXA and the initial scientific analysis conducted by the MMX Science Sub-Teams (i.e., post-2030). Leading this initiative are
the Centre National d'Études Spatiales (CNES) and the Museum National d’Histoire Naturelle (MNHM) in France and theGerman Aerospace Center (DLR) in Germany. Both are actively engaged in designing advanced curation facilities to receive,curate, and handle Phobos samples.
The Centre National de la Matière Extraterrestre (CNME, National Center for Extraterrestrial Materials) is a joint programsupported locally by the National Museum of Natural History (MNHN), Sorbonne University and the Institut de physique duglobe de Paris (IPGP) and, at the national level, by the French spatial and scientific research agencies (CNES and CNRS). The
CNME will be built in the historical Geology and Mineralogy Gallery of MNHN in the center of Paris. The CNME will be
designed to ensure long-term curation of unrestricted extra-terrestrial samples allocated to France from past and future space
missions such as MMX, together with existing major collections of extra-terrestrial samples including: the national meteorite
collection from MNHN, large polar micrometeorites collections and terrestrial analogues from the geology/mineralogy
collections. The CNME will consist in a clean-room infrastructure, divided in separated modules with ISO7 to ISO5
environments, together with an adjacent laboratory for sample preparations and experiments not requiring a cleanroom
environment. The CNME curation team will work under the supervision of CNES on the recently funded MARCUS project tobuild a dedicated apparatus for small sample (solid and gas) handling under restricted conditions (pure nitrogen glove boxes)and bio-contained environment. Instrumentation in the CNME will focus on acquisition of the basic properties on samples (fromµm to cm scales), including optical 2D and 3D microscopy and imaging, weighting, magnetic susceptibilities, scanning electron
microscopy, Raman and infrared (IR) microspectroscopy, XRD, with a dedicated suite of instruments to achieve initialcharacterization and cataloging of samples before allocation.
At the DLR Institute for Planetary Research in cooperation with the Museum für Naturkunde in Berlin, the Sample Analyses
Laboratory (SAL) and its extension, the Sample Curation Facility are currently being setup [3]. The target date for completionis in the summer of 2024. It is mainly dedicated to the analyses of unrestricted extra-terrestrial materials from sample return
missions. SAL will focus on spectroscopic, geochemical, mineralogical analyses at microscopic level. The instrumentation
includes a Malvern Panalytical Empyrean X-ray diffraction (XRD), a JEOL iHP200F Field Emission - electron microprobe
analyzer (FE-EMPA), a Field Emission - scanning electron microscope (FE-SEM), Keyence VHX-7000 3D microscope, and avis-IR-microscope (Bruker Hyperion 2000), all housed in a clean room that is currently being built. Samples will be processed,
handled and analyzed in pure nitrogen or vacuum conditions to minimize alteration and contamination.
Within the European Centre for Space Applications and Telecommunications (ECSAT) site of the European Space Agency(ESA), the recently established Vulcan Analogue Sample Facility (formerly SACF) is actively involved in the development of arobust European network dedicated to both existing and prospective extra-terrestrial analogue sample procurement, production,and supply chain management. The Vulcan Facility is further oriented towards advancing the scientific investigation of planetaryanalogues encompassing lunar, Martian, and other celestial bodies. This is accomplished through the provision of state-of-the-art benchtop instrumentation for fundamental analyses encompassing geochemical, mineralogical, and crystal lattice properties(SEM-EDS, XRD, FTIR and Raman). Additionally, the Vulcan Facility offers geotechnical property characterization capabilities(ViseSize particle size analyser, pycnometer, and TGA). Concurrently, Vulcan lends support to the curation of extra-terrestrial
materials and associated technology development initiatives (glovebox systems and a Double-Walled Isolator [DWI] with roboticarm equipped with a micromanipulator). The strategic focus of Vulcan on analogue samples is anticipated to play a pivotal rolein addressing the curation and research challenges associated with upcoming and future extraterrestrial sample return missions.
Between partners of any joint sample return activity, a tightly-coordinated approach on curation protocols, and mutually highlevel of technical proficiency and training, is fundamental to achieving the main goal of long-term curation: preparing fortechniques that have yet to be conceived, enabling testing theories that have not yet been developed, and catering for the ideas
and needs of future scientists.
The implications of capability development in Europe for handling returned samples extend beyond the MMX mission.
Establishing these curation facilities and developing a collaborative framework for distributed long-term curation will increase
the readiness of European involvement in future sample return missions. In particular, developments in sample handling andcuration infrastructure may be synergistic with that required by the long-term curation of Martian samples that are planned to be
returned by the NASA/ESA Mars Sample Return (MSR) campaign.
References
1.
Kuramoto K, Kawakatsu Y, Fujimoto M, et al (2022) Martian moons exploration MMX: sample return mission to
Phobos elucidating formation processes of habitable planets. Earth, Planets and Space 74:.
https://doi.org/10.1186/S40623-021-01545-7
2.
Usui T, Bajo K, Fujiya W, et al (2020) The Importance of Phobos Sample Return for Understanding the Mars-Moon
System. Space Sci Rev 216:49. https://doi.org/10.1007/s11214-020-00668-9
3.
Bonato E, Helbert J, Schwinger S, et al (2023) The Sample Analysis Laboratory at DLR and its Extension to Curation
Facility for MMX. In: 86th Annual Meeting of the Meteoritical Society. pp 6035–6035
4.
Aliz Zemeny and Kamini Manick (2023) Lunar Highland Simulant Selection of The Luna Analogue Facility Dust
Chamber For Future Missions – Space Resources Week, Luxembourg

The DLR Sample Analysis Laboratory – the final countdown
1

Joern Helbert , Enrica Bonato1, Ansgar Greshake2, Alessandro Maturilli1, Giulia Alemanno1, Aurelie van den Neucker1
and Lutz Hecht2
1
DLR, Institute for Planetary Research, Berlin, Germany
2
Museum für Naturkunde, Berlin, Germany

Laboratory measurements of extra-terrestrial materials like meteorites and ultimately materials from sample return missions cansignificantly enhance the scientific return of the global remote sensing data. This motivates the ongoing addition of a dedicatedSample Analysis Laboratory (SAL) to complement the work of well-established facilities like the Planetary Spectroscopy
Laboratory (PSL) and the Planetary Atmosphere Simulation LABoratory (PASLAB) within the Department of Planetary
Laboratories at DLR, Berlin. SAL is being developed in preparation to receive samples from sample return missions such as
JAXA Hayabusa 2 and MMX missions, the Chinese Chang-E 5 and 6 missions as well as the NASA Osiris-REX mission. SAL
is focusing on spectroscopic, geochemical, mineralogical analyses at microscopic level with the ultimate aim to derive
information on the formation and evolution of planetary bodies and surfaces, search for traces of organic materials or even tracesof extinct or extant life and presence of water.
SAL is currently being set up at the Institute for Planetary Research at the DLR location in Berlin-Adlershof in Germany. The
cleanroom environment is on the ground floor of the main DLR building in Berlin-Adlershof with a room for support
infrastructure in the basement below.
Procurement of the instruments is almost complete and first instruments are already been delivered. SAL will be equipped witha vis-IR-microscope (Bruker Hyperion 2000), a Malvern Panalytical Empyrean X-ray diffraction (XRD) system with BraggBrentano geometry which can be switched to parallel beam geometry, equipped with a Cu Kα source, 1Der detector andautomated incident beam optics, a Field Emission – scanning electron microscope (FE-SEM), a JEOL iHP200F Field Emission– electron microprobe analyzer (FE-EMPA), petrographic and stereo microscopes, Keyence VHX-7000 3D microscope and aset of gloveboxes.
The Bruker Hyperion 2000 and the Keyence VHX-7000 3D microscope are already in operation at PSL and PASLAB and havebeen used recently to study Ryugu sample A0112. The JEOL iHP200F is currently setup at JEOL in Freising, Germany.
Acceptance tests were successfully completed in March 2023. Commissioning, calibration, testing and initial training wascompleted in summer of 2023. The instrument has been used recently for work on meteorites and will be transferred to DLR inearly 2024 with an additional delta commissioning planned after final installation. The X-ray diffraction system has beendelivered in December 2022 and is currently in storage and will be setup as soon as the cleanrooms are ready. SEM procurement
is currently under way with a delivery expected in summer of 2024.
In collaboration with the Natural History Museum (MfN) in Berlin, SAL will also have the expertise and facilities for carryingout curation of sample return material which will be made available for the whole European scientific community. DLR isalready curating a 0.45 mg of Lunar regolith collected from the Luna 24 Soviet mission and the first analyses of the material arebeing planned.
Currently, the curatorial expertise is being developed on the existing expertise from the Meteorite Collection based at the MfN
and in collaboration with the JAXA and NASA curation facilities. Current curators, together with the younger generation arebeing trained and working on skillset exchange

Curation of Extraterrestrial samples in France and the future center for extraterrestrial
materials in Paris.
J. Duprat1, J.-C. Viennet1, M. Roskosz1, B. Doisneau1, S. Pont1, M. Verdier-Paoletti1, S. Bernard1, M. Gounelle1,
J. Aléon1, P. Sans-Jofre1, B. Zanda1, G. Avice2, F. Moynier2, R. Brunetto3, C. Pilorget3, F. Poulet3, C. Engrand4,
L. Delauche4, E. Dartois5, J. Gattacceca6, C. Maurel6, L. Piani7, Y. Marrocchi7, A. Barucci8, L. Bonal9,
L. Lemelle10, A. Simionovici11, G. Libourel12
1

IMPMC, CNRS-MNHN-Sorbonne Université, UMR 7590, 57 rue Cuvier, Paris, France ; 2Université Paris Cité,
Institut de physique du globe de Paris (IPGP), CNRS, Paris, France ; 3IAS, Université Paris-Saclay, CNRS,UMR 8617, Orsay, France ; 4IJCLab, Université Paris-Saclay, CNRS/IN2P3, Orsay, France ; 5ISMO,
Université Paris-Saclay, CNRS, Orsay, France, 6CEREGE, Aix-Marseille Université, CNRS, INRAE, IRD, Aixen-Provence, France, 7CRPG—CNRS 15 rue Notre Dame des Pauvres, BP 2054501 Vandœuvre-lesNancy, France, 8LESIA-Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris
Cité, 92195 Meudon Principal Cedex, France, 9IPAG, Université Grenoble Alpes; 38000 Grenoble, France,
10
LGL-TPE, CNRS, UCBL, ENS de Lyon, 11ISTERRE, CNRS, Université Grenoble Alpes, 38058 Grenoble,
France, 12Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, LAGRANGE, France.

The coming decade will witness important developments in curation facilities dedicated to pristine samples fromspace missions. The return of samples from asteroid Bennu by the OSIRIS-REx NASA-led mission [4] is imminent
and, on a longer term, samples will be returned from the Martian moon Phobos by the MMX JAXA-led mission[5]. After 2030, samples from the Martian surface are expected to be returned to Earth by the NASA/ESA Mars
Sample Return (MSR) mission [6]. Advanced curation studies are on-going [9, 10] in major curation facilities at
JAXA and NASA [7-9] while others facilities are currently into construction, such as the SAL in Berlin [see e.g.
11 and this meeting]. Many laboratories in France have experience in handling samples from spatial missions orfrom existing collections of extra-terrestrial materials (meteorites, micrometeorites, IDPs…). These experiences
cover a whole range of expertise from curation itself to dedicated samples handling (e.g. micromanipulation,
fragmentation…), first-order characterization by non-invasive or non-destructive techniques and dedicated sample
preparation (e.g. thin and ultra-thin sections, polished sections, …) in clean-room environments.
The CNME project was launched in 2022 to build a national curation facility for extra-terrestrial materials at
MNHN. This project is supported, at the national level, by the French spatial and scientific research agencies(CNES and CNRS) and will be supported locally by the National Museum of Natural History (MNHN), Sorbonne
University and the Institut de physique du globe de Paris (IPGP). This project will benefit from the local experiencein curation of existing collection of meteorites and micrometeorites and from expertise developed in other Frenchlaboratories. A key objective of CNME will be to ensure the long-term curation of a fraction of samples from thefuture MMX JAXA-led mission [5]. As a result of on-going agreements between JAXA and the French space
agency CNES and ESA, a fraction of Phobos (MMX) samples are expected to be transferred to the CNME at
MNHN and after the period of initial description at JAXA-ISAS sample receiving laboratory and after the firstscientific analysis by the MMX Science Sub-Teams (i.e. after 2030). In the long-term, the CNME will be designed
to allow the reception of un-restricted samples from MSR mission, i.e. once they will be out of the Sample
Receiving Facility.
The design of CNME will be modular to allow flexible configuration of different environments for the curation ofsamples from different space missions. The CNME clean-room infrastructure will be divided in separated modules(ISO7 to ISO5 [24]) environments, together with a laboratory dedicated to sample preparations. It will containsecured cabinets and glove boxes under controlled atmospheres (dry and purified N2, Ar, vacuum, …). In the longterm perspective of MSR, the CNME team is involved in the MARCUS project to study, under the supervision of
CNES, a dedicated apparatus for small sample (solid and gas) handling in clean and bio-contained (BSL4-like)environment. The CNME will include a dedicated space for rehearsal activities on the MARCUS apparatus (before
operation in BSL4-like laboratories). Instrumentation in CNME will focus on acquisition of the basic properties
on samples with sizes going from µm up to cm scales, including optical 2D and 3D microscopy and imaging,weighting, magnetic susceptibility measurements, scanning electron microscopy, XRD, Raman and infrared (IR)micro-spectroscopy with a dedicated suite of instruments, to achieve initial characterization and cataloguing ofsamples. The control of terrestrial contamination within CNME cleanrooms will be achieved by real-timemonitoring of inorganic, organic and biological contamination.
The CNME will include instruments and advanced storage facilities developed by several French laboratories. The
magnetic environment of the samples and the magnetic properties of the handling tools will be monitored to ensurepreservation of the original paleomagnetic record of the samples. The CNME will develop research programs to
improve existing curation techniques and new technological solutions for the mid to long-term curation of volatileelements contained in samples collected by future space missions, e.g. ice and gas from cometary objects orplanetary atmospheres (see G. Avice et al. this meeting). A specific setup will be developed at IAS in order toallow a multi-scale (from mm down to µm) IR reflectance micro-imaging characterization of samples. The analysis
will be fully non-destructive and non-invasive with no need for specific sample preparation, it will be performed
within a dedicated bench in a controlled atmosphere (e.g., N2). Other setups for samples preparation and/or firstorder charaterization are currently in study in French laboratories with the aim to built a national network of experts
in curation-related activities. At the international level, the CNME team will develop in-depth collaboration withother teams currently managing major curation centers in Europe and on a world-wide scale (see A. Hutzler et al
this meeting).
The CNME will ensure the long-term curation of the MNHN historical meteorite collection that include a richpanel of Martian samples (Shergottites, Chassignites, Nakhlites) [17] and several emblematic primitive chondrites(e.g. Orgueil CI-chondrite). The MNHN meteorite collection is actively used for cosmochemistry research projects
and is constantly growing with new additions every year, thanks to collections performed by a joint team from
CEREGE and MNHN in Atacama Desert (see e.g. [14]). The CNME will also have the responsibility for the longterm curation of micrometeorite collections recovered from both Greenland and Antarctica [15] including theConcordia micrometeorites collection (currently in a dedicated curation cleanroom at IJCLab) that contains
thousands of micrometeorites with minimal terrestrial weathering [16]. Beside these collections, CNME will also
ensure the long-term curation of samples from the Chinese mission Chang’e5 recently donated to France.
In this presentation, I will summarize the general landscape of curation activities in France and present the current
status of the CNME project.
Acknowledgement: The CNME is a joint project supported by MNHN, IPGP, Sorbonne University, University
Paris Cité, CNES and CNRS. The curation-related instruments and apparatus currently under development benefit
from funding by Région Ile de France (DIM-ACAV+ contract C3E), CNES, CNRS, MNHN and ANR contract(COMETOR 18-CE31-0011). The collection of micrometeorites benefited from the pluri-annual funding by IPEV
and PNRA (Program #1020)
References: [1] Brownlee D. (2014) Ann. Rev. Earth Planet. Sci. 42, 179-205. [2] Yano H., et al. (2006) Science
312, 1350-1353. [3] Watanabe S., et al. (2019) Science, eaav8032. [4] Lauretta D.S., et al. (2017) Space Sci.
Rev. 212, 925-984. [5] Kuramoto K., et al. (2022) Earth, Planets and Space 74, 12. [6] Beaty D.W., et al. (2019)
Meteorit. Planet. Sci. 54, S3-S152. [7] Yada T. et al. Meteorit. Planet. Sci. 49, 135-153 [8] Evans C., et al.
(2018) 42, B4.2-49-18. [9] McCubbin F.M., et al. (2019) Space Sci. Rev. 215, 48. [10] Hutzler A. et al. EUROCARES D7.1 Final technical Report. [11] Helbert J., et al. (2020), EPSC2020-250. [12] ISO 14644-1 [13]Caillet Komorowski C.L.V. (2006) Geol. Soc. London Spec. Pub. 256, 163-204. [14] Gattacceca et al. (2011)
MAPS 46, 1276-1287, Hutzler et al. (2016) MAPS 51, 468-182 [15] Maurette M., et al. (1986) Science 233, 869872. Maurette M., et al. (1991) Nature 351, 44-47. Duprat J., et al. (2007) Adv. Space Res. 39, 605-611. Rojas J.,
et al. (2021) Earth Planet. Sci. Lett. 560, 116794. [16] Duprat J., et al. (2010) Science 328, 742-745.

Mars Sample Return: curation activities and planning.
Aurore Hutzler1, Andrea D. Harrington2, William E. Page3 and Alvin L. Smith2.
1
ESTEC, European Space Agency, The Netherlands
2
NASA, Johnson Space Center, Houston, TX, USA
3
Jet Propulsion Laboratory, USA
Curation of extra-terrestrial samples is a multifaceted process that aims to balance the conservation of a collection with its
efficient use. Therefore, a robust curation plan will maximize the science conducted in the first years after sample return while
ensuring a representative collection remains available to enable science for decades.
The Mars Sample Return (MSR) campaign, initiated in 2020 with the launch of the Perseverance Rover, represents aninternational collaboration between the United States National Aeronautics and Space Administration (NASA) and the European
Space Agency (ESA) for the purpose of bringing Martian geological samples back to Earth for scientific investigations. This
ambitious undertaking marks the first instance of sample return from another planet and the first return classified as Restricted
since Apollo 14. The Restricted classification requires rigorous backward planetary protection requirements (BPP), which
impacts how samples can be curated and analysed.
NASA and ESA have agreed to jointly proceed on science and curation and are in the formulation phase of the joint NASA/ESA
Sample Receiving Project (SRP). After the sample arrive on earth and are transported to the Sample Receiving Facility, initialcharacterization begins. The aim on initial characterization is to generate a robust catalogue, which is a mandatory element tothe allocation process. Sample requests for scientific research accomplished in the first years after sample return will be openly
competed and jointly selected by ESA and NASA; this includes allocations for objective science completed within the SRP (firstplanned AO nominally in 2026) as well as opportunity science outside of the SRP. Proposals from a consortium of institutions
proposing a coordinated analysis plan will be encouraged, to ensure efficiency and accountability.
While the Martian samples are expected to be back as soon as 2033, preparatory activities for protocols, hardware andinfrastructure are underway. NASA and ESA have selected several working groups from the scientific community to advise on:1) measurements to be conducted on the samples, 2) appropriate contamination control parameters, and 3) necessary
requirements for handling and analysing the collection. Several curation and engineering teams in the United States and in Europe,
coordinated by the NASA/ESA Joint Curation Office (JCO), are in close interaction with the NASA/ESA Joint Science Office
and are working on developing hardware and strategies for the Sample Receiving Facility. The JCO is developing a curation
plan following guidelines from the NASA NPR 7100.5 [1] (pending validation by NASA and ESA upcoming agreements).
The JCO is also considering long-term curation of the collection, separate from the SRP as part of their planning. It is expectedthat long-term curation might not require high-containment, and that while only one Sample Receiving Facility is planned, there
might be several MSR curation facilities.
Latest updates on curation, science, and R&D planning will be shared, with an emphasis on synergies between the MSR
curation team and the science community.
References[1] https://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_7100_0005_&page_name=main&search_term=7100.5

Mars Sample Return: Considerations for the Curation of Astromaterials from a Restricted Planet
Andrea D. Harrington1, Aurore Hutzler2, and Francis M. McCubbin1
1
NASA, Johnson Space Center, Houston, TX, USA
2
ESTEC, European Space Agency, The Netherlands
The joint NASA/ESA Mars Sample Return (MSR) campaign is underway. The Perseverance Rover has already collected areturnable sample suite currently cached at Three Forks and the pairs to these samples are stored on the Rover with morecompelling samples planned to be collected. The MSR collection would represent the most geologically diverse astromaterial
collection ever returned and should provide information on topics ranging from Martian geological and biological history to
Martian environmental hazards and in situ resource utilization to support potential human exploration [1]. Although Jezero
Crater and the surrounding area are not Mars special regions, the scientific opinion is that Mars as a whole is of significant
interest to the process of chemical evolution and/or the origin of life. Therefore, due to possibility, however remote, that the
samples could contain extraterrestrial life, MSR is classified as a Category V: Restricted Earth Return mission by the NASA
Planetary Protection Office. As a result of this classification, a MSR Sample Receiving Facility (SRF) must not only provide apristine environment to ensure samples are protected from terrestrial contamination for scientific investigations, but it mustalso provide high-containment to isolate the samples from Earth’s biosphere until the samples are deemed safe for release
and/or sterilized.
The SRF is first and foremost a curation facility, however it will be utilized for an array of tasks and scientific objectives,
including:• Receive the flight hardware containing the sample collection (e.g., Earth Entry System, Orbiting Sample)• Deintegrate the sample tubes from the hardware and put in a stable state• Characterize the sample tubes (Pre-Basic Characterization)• Open the sample tubes (e.g., collect headspace gas, extract samples while maintain stratigraphy)• Perform initial sample characterization and cataloging• Conduct a sample safety assessment• Execute preliminary examination of samples for science• Enable select competed/early science• Prepare, sterilize, and distribute samples for science outside of the SRF• Sample isolation/storage
The SRF is not intended to be the long-term curation facility for Martian samples. The nominal utilization period for the SRF
is anticipated to be 2-5 years. However, to account for possible delays in schedule or the identification of extant life, thisanticipated period of time must be flexible to accommodate schedule extensions and contingency plans. Due to the highcontainment requirements, a traditional receiving/curation facility cannot be utilized for MSR.
As a result of the complexity of designing, constructing, and operating a contamination-controlled high-containment facility,
NASA initiated an assessment of current technologies. Personnel toured both contamination-controlled and high-containment
facilities around the world, exploring the implementation of new technology and standard practices. The report, entitled:“Tours of High-Containment and Pristine Facilities in Support of Mars Sample Return (MSR) Sample Receiving Facility(SRF) Definition Studies” compiles the knowledge of experts in their fields and offers recommendations for the best pathforward [2]. NASA and ESA have used this data, as well as outputs from numerous MSR science working groups, to performthe Mars SRF Assessment Study (MSAS) and the European Extraterrestrial Sample Infrastructure (EETSI) System Study.
While EETSI investigated the preliminary design, costs, and schedules for new, traditionally built fixed SRF and Sample
Curation Facilities (SCF), MSAS was a scoping study, designed to assess the feasibly of utilizing traditional versus more novel
infrastructure, specifically:
1. Lease and renovation of existing space
2. Construction of a new, traditional fixed facility
3. Construction of a modular facility (new or within an existing building)4. Construction or renovation of a hybrid facility to address requirements with multiple modalities that may include a
combination of modalities 1-3.
The assessment also considered the following aspects of the SRF for each modality:• Ability to meet requirementso Regulatory
o Planetary protectiono Contamination controlo Science and curation• Ability to meet changing needs for equipment, timelines, and facility use• Timelines for design, construction, commissioning, installation of equipment, testing, training, and operational
readiness drills• Cost for construction and operation, including those associated with hazard resilience• Ease of access for international users• Decommissioning, repurposing, sale, or lease following use of the facility• Uncontained preparatory laboratory spaces• Uncontained ancillary spaces• Waste management
The outputs for MSAS and EETSI have been critical to understand the potential trades and identify priorities for the SRF.
However, while options were able to be refined, a second phase (MSAS2) will develop high-concept designs at multiple
locations in order to optimize the technical capabilities, cost, and schedule of the SRF. As part of the next steps in planning, theNASA/ESA Mars Sample Receiving Project (SRP) Joint Curation Office (JCO) is developing a curation plan following
guidelines from the NASA NPR 7100.5 [3] and supporting the Measurement Definition Team (MDT). The MDT is charteredto evaluate the measurements and instrumentation needs for the SRF. Outputs from this team, as well as the Sample Safety
Assessment Protocol (SSAP) Tiger Team, will be critical for SRF design. Upon completion of MSAS2, the SRF designconcepts would be utilized to inform site-specific design but the location of the SRF will not be finalized until NASA’s
completion of the National Environmental Policy Act (NEPA) process.
Every sample return mission offers scientists and engineers unique challenges and opportunities, MSR is certainly not an
exception. While differences in robotics and spacecraft are often apparent, differences in the approach for the curation of agiven collection are usually more nuanced. NASA’s Astromaterial Acquisition and Curation Office, and other international
space agency partners, have developed strong foundations of best-practices and lessons learned. Although MSR represents thefirst Restricted Earth return in five decades, the knowledge gained from the development and operations of the Lunar
Receiving Laboratory are informing the potential curation strategies for MSR. Whether the SRF is reutilized by NASA for
another Restricted Earth return after the MSR samples are deemed safe or turned over to a partner for other types of highcontainment work, the knowledge gained during technology development, SRF design, construction, and operations will lay
the foundation for sample return missions for the next five decades.
References[1] Czaja A. D. et al. 2023. Meteoritics & Planetary Science 58: 885-896. [2] Mattingly R. L. et al. 2020. JPL/NASA Report.
[3] https://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_7100_0005_&page_name=main&search_term=7100.5

Fostering future missions and curation: fine-particle simulant characterization for a lunar highland
testbed (ESA, European Astronaut Centre - EAC)
Aliz Zemeny1 and Kamini Manick1
1

European Space Agency (ESA), Vulcan Analogue Sample Facility, European Centre for Space Applications andTelecommunication (ECSAT), Fermi Avenue, Harwell Campus, Oxfordshire, United Kingdom

In the framework of the European Centre for Space Applications and Telecommunications (ECSAT), the UK site of the European
Space Agency (ESA), the Vulcan Analogue Sample Facility is actively engaged in the establishment of a robust European
network devoted to the acquisition, production, and management of extraterrestrial analogue samples (or simulants), both
existing and prospective. The Vulcan Facility is primarily oriented towards advancing scientific inquiries into planetaryanalogues, encompassing celestial bodies such as the Moon and Mars. This pursuit is facilitated through the deployment ofbenchtop instrumentation for fundamental property analyses, and support for the curation of extraterrestrial materials and thedevelopment of associated technologies. European simulant priorities were determined following a user survey and simulant
supplier workshop in 2022 (Table 1).
As part of supporting the European simulants network, Vulcan's role encompasses choosing the optimal fine-particle highland
feedstock option for the ‘Dust Chamber’ [1] of the Luna Analogue Sample Facility in Cologne, Germany (EAC, ESA). The
selection process entails a comprehensive exploration of the European network of simulant providers and both commercial andacademic laboratories, entailing an exhaustive evaluation of the availability and logistical aspects of materials accessible in themarket. This consideration encompasses critical factors such as loading times and associated costs. Furthermore, a rigorous
assessment of simulant properties is conducted, including but not limited to particle size distribution, shape, and abrasivity. These
parameters hold significant importance in the context of primary geotechnical and geomechanical objectives within the ‘Dust
Chamber’.
Nonetheless, these deliberations serve to refine the pool of potential highland simulants obtainable in Europe. Ultimately, themost suitable simulant candidate will be meticulously chosen to facilitate comprehensive testing of geotechnical and engineeringrelated activities within the Dust Chamber. It comprises due diligence of the full simulant supply chain (including assessment of
the source site, excavation and processing methods, and quality control). Consequently, discerning selection process aims tocontribute substantively to the accumulation of essential knowledge, thus enhancing our readiness for the upcoming sample
return and human lunar surface missions in this decade.
Table 1. Priority activities, among 36 simulant users surveyed in 2022 (35 European-based, 1 Japan-based), centring around exploration
hardware and resource extraction studies. Red: 25-28%; Yellow: 11-16%; Green: 3-8%; Grey: No data.
Lunar

MartianAsteroids /Meteorites

Other

Spacecraft, instruments and/or
software
ISRU(Resource extraction)
ISRU(Additive manufacturing)
ISRU(Unspecified)
Planetary Science Research

References[1] A. Zemeny and K. Manick (2023) Lunar highland simulant selection of the Luna Analogue Facility Dust Chamber for future
missions – Space Resources Week, Luxembourg

Nanoscale infrared characterization (AFM-IR) of Ryugu samples returned by the Hayabusa 2
space mission
J. Mathurin1, E. Dartois2, A. Dazzi1, A. Deniset-Besseau1, L. Bejach3, C. Engrand3, J. Duprat4, Y. Kebukawa5, H. Yabuta6, H.
Yurimoto7, T. Nakamura8, T. Noguchi9, R. Okazaki10, H. Naraoka10, K. Sakamoto11, S. Tachibana11,12, S. Watanabe13, Y.
Tsuda11, and the initial-analysis IOM and STONE teams
1

Institut Chimie Physique (ICP), Univ. Paris-Saclay/CNRS, 91405 Orsay, France
2
ISMO, Univ. Paris-Saclay/CNRS, 91405 Orsay, France
3
IJCLab, Univ. Paris-Saclay/CNRS, 91405 Orsay, France
4
IMPMC/MNHN, SU, Paris, France
5
Faculty of Engineering, Yokohama National University, Japan
6
Hiroshima University, Higashi-Hiroshima 739-8526, Japan
7
Hokkaido University, Sapporo 060-0810, Japan
8
Tohoku University, Sendai 980-8578, Japan
9
Kyoto University, Kyoto 606-8502, Japan
10
Kyushu University, Fukuoka 812-8581, Japan
11
ISAS/JAXA, Sagamihara 252-5210, Japan
12
The University of Tokyo, Tokyo 113-0033
13
Nagoya University, Nagoya 464-8601, Japan.

The distribution of chemical bonds in organic matter (OM) of interplanetary samples (meteorites andmicrometeorites) can be efficiently and non-destructively characterized using infrared vibrational spectroscopy (FTIR) [1].
Conventional FTIR microscopy provides a global view of the dust grain physico-chemical composition but remains spatiallylimited by the diffraction. In state-of-the-art synchrotron-based FTIR microscopy, the typical spot sizes in the mid-IR range
can, at best, sample a few µm. This spatial resolution limitation often hampers a direct comparison with complementary
techniques such as isotopic imaging with NanoSIMS, transmission electron or X-ray microscopy. Such IR diffraction
limitation can be circumvented using AFM-IR microscopy [2]. AFM-IR is now a well-established microscopy technique in thevibrational field, combining an atomic force microscope (AFM) and a tunable IR illuminating source to detect photo-thermal
effect and access chemical information. This technique is applied in a wide diversity of scientific fields [3] and we recently
used it to analyze various extraterrestrial samples [4-8]. For this study the tunable IR illuminating source is a QCL laser with aspectral range from 1900 cm-1 – 900 cm-1 with a top-down illumination. This configuration allows two modes of acquisition. In
the first one, the wavenumber is fixed and the tip moves along the surface, allowing to acquire simultaneously AFM
topography and an IR absorption map of the sample at the selected wavenumber. In the second one, the tip position is fixed ona sample position and the IR laser is tuned to explore the whole available spectral range of the QCL laser, giving access tolocal IR spectra at the point of interest.
Ryugu samples from chamber A (surface) and chamber C (sub-surface) were received from the “IOM” and “Stone”
Hayabusa2 initial analysis teams. Several samples from chambers A and C were prepared by crushing small fragments on
diamond windows, down to a thickness of ~1 µm. Because of the high resolution of AFM-IR (tens of nanometers), regions ofinterest were first localized and selected using synchrotron-based FTIR microscopy [8].
Figure 1: Study of chamber C sample C109-04. B1: 3 x 3µm RGB composite image combining the AFM-IR
absorption mapping obtained at different wavenumbers
corresponding to the absorption of Si-O silicates (1020
cm-1, green), C=C (1600 cm-1, blue) and C=O (1720 cm1, red). The size of the image here corresponds to the sizeof one pixel in the synchrotron maps - B2: AFM
topography of the 3 x 3 µm area studied in AFM-IR B3: optical image - B4: from top to bottom : average IR
synchrotron spectra obtained on the whole sample, local
spectra obtained by AFM-IR highlighting the presenceof OM with and without a C=O signature at 1720 cm-1,
on the locations highlighted by arrows in B1. The red,
blue and green dashes indicate the wavenumber positionsof the IR mapping with the same color - B5-B7: IR maps
obtained by transmission synchrotron µFTIR at same
wavenumber (and corresponding colors) as the AFM-IR
maps. Adapted from [7]A large-scale map (20 µm x 20 µm) was first recorded to characterize the main components' distribution within the sample
with a spatial resolution of ~75 nm [8]. As the OM contribution in the IR spectra is weaker than that of minerals, highly
spatially resolved maps of 3 x 3 µm in size were acquired with a lateral spatial resolution of ~25 nm. It was then possible tolocalize OM inclusions in the samples (Fig.1 – B1) by comparing the signal from the Si-O of the silicates (Fig. 1 – B1 ingreen) and that from the OM contributions of the C=C absorption (Fig. 1 – B1 in blue) and C=O absorption (Fig. 1 – B1 in
red). On the larger OM inclusion displayed in Fig. 1 – B1, the OM signal is a mix between C=C and C=O (which appears in
purple), but chemical heterogeneities are observed at small scales: parts of the inclusion seem to exhibit local enrichment in
C=O (redder) or in C=C (bluer). Local AFM-IR spectra were recorded on these spots, showing locally different C=C and C=O
contributions (Fig.1 – B4) [7].
Based on this first measurement, a more complete analysis of various samples was conducted either on whole-rocksamples or on IOM extracted from chambers A and C samples [9]. The results obtained not only confirmed the heterogeneityof the OM distribution already observed but also highlight the fact that OM is mainly distributed in two phases, a diffuseorganic component intimately mixed with the mineral matrix and nanoglobule-like organic particles (Fig. 2). These particles
are texturally resembling nanoglobules present in primitive meteorites and were identified in both whole-rock and IOM
samples from chambers A and C Ryugu samples. The local IR spectra of nanoglobule-like particles also clearly showenhanced carbonyl (C=O) and CH contributions with respect to the diffuse organic matter in Ryugu whole-rock and IOM
residue (Fig. 2 – (c)). Such spectra are compatible with that of organic residues formed from UV or ion irradiated ices at low
temperatures, simulating the environment of the outer regions of the protoplanetary disk, or in the protosolar cloud.

Figure 2: Whole-rock Ryugu sample A0108-19. (a) RGB image of the region including an organic nanoglobule-like particle (C=O at 1720
cm−1 in red, C=C at 1600 cm−1 in green, CHX at 1460 cm−1 minus 1520 cm−1 in blue). The white line shows the location of individual AFMIR spectra taken across the nanoglobule-like feature. The colored dots (S1 to S3) correspond to average spectra taken on each side (S1 andS3 in blue) and on the nanoglobule-like feature (S2 in red). (b) Intensity ratios corresponding to CHX/C=C (1460 cm−1/1600 cm−1) and
C=O/C=C (1700 cm−1/1600 cm−1) along the white line shown in (a). The location of the S1 to S3 spectra is recalled on the left axis.
(c) Average spectra on each side (blue, S1 and S3) and on the nanoglobule-like feature (red, S2). The red dot-dashed line spectrum labelled‘Nanoglobule-like’ is obtained by scaling the average of S1 and S3 spectra to the same silicate band intensity as in the S2 spectra, and by
subtracting this scaled spectrum from S2. The resulting ‘Nanoglobule-like’ spectrum is thus freed from the matrix contribution underneaththe globule. The nanoglobule-like spectrum shows elevated CHX signal (intense methyl and methylene deformation modes at ∼1460 cm−1and ∼1370 cm−1), as well as high carbonyl contributions around 1700 cm−1. The blue dot-dashed line spectrum labelled ‘Matrix’ corresponds
to the expected contribution from the matrix for equivalent probe depth as for the nanoglobule-like spectrum. Adapted from [9].

AFM-IR measurements demonstrate the presence of organic inclusions intimately mixed with minerals in Ryugu samples
at the sub-micron scale. Focusing on the OM-rich zones of Ryugu samples it is possible to unveil, without any chemicaltreatment, the IR signature in the chemical bondings of chemical OM heterogeneities as well as the sub-micrometric spatial
distribution of the different components. This study shows that OM exists in (at least) two forms in Ryugu samples, as adiffuse phase in the minerals matrix, and as isolated inclusions resembling nanoglobules.
References[1] Dartois E. et al. 2018 Astron. Astrophys., vol. 609, p. A65. [2] Dazzi A. at al. 2005 Opt. Lett., vol. 30, no. 18, pp. 2388–
2390. [3] Dazzi A. and Prater C. B. 2016 Chem. Rev., vol. 117, no. 7, pp. 5146–5173. [4] Mathurin J. et al. 2019 Astron.
Astrophys., vol. 622, p. A160. [5] Kerraouch I. et al. 2022 Geochim. Cosmochim. Acta, vol. 334, pp. 155–186. [6] Kebukawa
Y. et al.2023 Icarus, vol. 400, p. 115582. [7] Yabuta H. et al. 2023 Science 80, vol. 379, no. 6634. [8] E. Dartois et al. 2023
Astron. Astrophys., vol. 671, p. A2, Mar. 2023. [9] Mathurin J. et al., in revision.

Sampling and curation of volatile elements in the new era of sample return missions
Guillaume Avice1, Frédéric Moynier1, C. Mustin2, Jean Duprat3
Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
2
IMPMC, Muséum National d’Histoire Naturelle, Sorbonne Université, CNRS, Paris, France
3
Centre National D’Etudes Spatiales (CNES), France
1

The scientific community has been entering a new era of sample return missions with the successful Hayabusa 1&2 (JAXA) andfuture OSIRIS-REx (NASA) missions, the future missions of samples return from Mars (Mars Sample Return mission, NASAand ESA) and its moon Phobos (MMX, JAXA). Other than their inner scientific values, sample return missions are of key
scientific importance as they trigger the development of suites of state-of-the-art analytical techniques in terrestrial laboratories
to conduct exhaustive characterization of the returned samples (petrography, mineralogy, chemical analyses etc.). Among theseinvestigations, measuring the elemental and isotopic composition of volatile elements in extraterrestrial samples is a high priority
scientific target as they can be used to understand the origin of planetary atmospheres and of water in terrestrial planets (e.g.,[1]). More broadly, such measurements could provide answers to the question: Why is the Earth habitable? Such investigations
rely on the ability to conduct a proper curation of the samples containing volatile elements. A recent study highlighted the needfor developing advanced curation techniques for volatile-rich samples [2] and a recent experiment developed by US-based
scientists opened lunar core containers returned to Earth by the Apollo astronauts in order to sample volatile elements (see ref. 3).
Developing new curation techniques is also one of the goals of the future curation center CENAME (a Center National for
Extraterrestrial Materials) which will be built at the French Musée National d'Histoire Naturelle (MNHN, Paris, France) incollaboration with the Institut de physique du globe de Paris (IPGP, France) (see J. Duprat et al., this meeting). This is also one
goal of the project MARCUS led by CNES (PI. C. Mustin) and which is part of the new French initiative PEPR Origins: fromplanets to life.
In 2019, the Hayabusa2 mission successfully sampled over 5 grams of solid samples from the surface and subsurface of theasteroid Ryugu. The preliminary scientific investigations revealed that Ryugu samples are similar to primitive carbonaceous
material similar to Ivuna-type meteorites but with less alteration than identified in these meteorites [4]. Having pristine samples
from carbon-rich asteroids also allows to put new constraints on the role of these bodies in the delivery of volatile elements to
Earth [5]. Recent measurements of the D/H ratio of hydrogen contained in Ryugu samples revealed that carbonaceous-typematerial could have delivered up to 3% of Earth's water [6]. Importantly, the sealing technique adopted for closing the sample
capsule consisted in an aluminum metal seal [7], maximizing the chances to retain extraterrestrial volatile-rich elements such as
noble gases. A quick recovery of the sample capsule followed by careful onsite curation protocols [8] allowed to recover the gas
originally contained in the sample capsule. Results obtained by a preliminary study reveal that, despite a certain degree ofcontamination by the Earth's atmosphere, the gas sampled during the mission is extraterrestrial with a clear contribution fromsolar-wind derived gases [9]. Investigations also revealed that the Al-seal partially re-opened during Earth’s entry due to thestrong deceleration when the parachute deployed.
The technical developments and sample handling protocols used before, during and after the return of samples by the Hayabusa2
mission are the best and most recent examples of advanced curation techniques for volatile-rich elements collected during space
missions [8,9]. Therefore, they represent a reference starting point for improving the current curation protocols and developing
new solutions. Ryugu samples are thus providing perfect opportunity to assess the quality of the current techniques of curationof volatile-rich extraterrestrial samples. In this presentation we will show how Hayabusa2 samples have the potential to provide
key information on the state-of-the-art of curation techniques and possible improvements.
Gas samples from Ryugu allocated by the JAXA curation center will be delivered to IPGP in fall 2023. Noble gases (Ne, Ar, Kr
and Xe) elemental and isotopic composition will be immediately measured in order to : i) evaluate if the different samples
prepared by the curation team have the same composition (NT1 vs NT2 sample) ; ii) compare with published data (e.g., [9]) forNT1 sample and evaluate if the composition of the gas has evolved since the preliminary investigations. Samples will then be
stored in distinct conditions (closed and exposed to room pressure and temperature for one sample, closed and attached to a turbo
molecular pumping station for another sample, closed and exposed to moderate vacuum for another sample). New measurements
will then be conducted after 6-9 months to assess which storage conditions is the most appropriate. Results will be shared anddiscussed with the JAXA curation team the international community concerned on this aspect of the curation of extraterrestrial
samples.

Figure 1: Summary of the sample allocated by the JAXA curation center. The original samples NT1, NT2 and NT5(bottles, ref. 8) are identified as well as the three different pipettes to be drawn from the bottle by the JAXA curation
team. Samples will be measured at different times and stored in different conditions to evaluate curation techniques.

In this presentation we will also describe future long-term developments for the curation of volatile-rich samples. One
development will involve testing new materials for the sample containers (e.g., TiN covered Titanium coupons used for the
preparation of Perseverance sample tubes and gently provided by colleagues from JPL). We will also improve curation protocols(short- and long-term monitoring) and develop new solutions for vacuum containers.
References[1] Avice G. & Marty B. 2020. Space Science Reviews 216:36. [2] McCubbin et al. 2019. Space Science Reviews 215:48. [3]Parai et al. 2022. Apollo 17 – ANGSA Workshop, LPI Contrib. N°2704:2028. [4] Yokoyama et al. 2022. Science
379:eabn7850. [5] Paquet et al. 2023. EPSL 611:118126. [6] Piani et al. 2023. Astrophysical Journal Letters 946:L43.
[7] Okazaki et al. 2017. Space Science Reviews 208:107-124. [8] Miura et al. 2022. Earth Planets Space 74:76. [9] Okazaki etal. 2023. Science 379:eabo0431.

Machine Learning Data Analyses for Asteroid and Micrometeorite Samples

Lewis Pinault1 and Hajime Yano2
School of Natural Sciences, Birkbeck College, Gower Street, London WC1E 7HX, United Kingdom
2
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara,
Kanagawa 252-5210 Japan1

We have developed and trained Machine Learning (ML) convolutional network models on aerogel-captured meteoroid
samples of the Tanpopo [1] missions onboard the International Space Station using new camera, recording, and processing
techniques that greatly speed and automate their identification and classification. This technique moves beyond datasets thathave already been laboriously centred, focused, scaled, imaged, and classified to various types by human researchers, andbuilds on prior systems [2] to open the door to automated transits by microscope across the Tanpopo aerogel panels at
approximately 500x500 pixel increments, at different focal lengths, with images then fed directly into core ML Object
Detection programme. The programme then uses its object detection/localisation capabilities to automatically draw boundingboxes around the object or objects of interest in each image, and to automatically run a confidence prediction of whichclassification of the types it might be, displayed both on the image and as a searchable table [3].
The time-and-manpower gains that can be affected by ML became clear with its further application to the Ryugu A0180
sample. Hundreds of nano-CT scans were conducted to create segmented images [4] whose cross-sections helped reveal
characteristic micro-features within the sample such as voids, cracks, and micro-chondrules of particular interest. For an
example, human-eye examination of void evidence and 3D distribution in cross-section allowed re-integration of the images toreveal the voids in full dimension. This manual process of identifying and classifying evidence of voids in cross-section is ripefor ML identification, classification, and reintegration using the methods we have developed. Moreover, the data gained bymanual imaging of A0180 now forms a robust training data set for applying to more porous and aggregate samples such as
unmelted micrometeorites collected in the terrestrial environment.
Thus, 3D optical images, nano-CT data, and external and internal SEM images of Ryugu asteroid samples returned by
Hayabusa2 can be archived at international research institutions to create further training data for searching the diversity
among different groups of asteroid samples and for practically comparing characteristic micro-structures with the wider suiteof micrometeorite collections. In this manner, it may also be possible for the ML modelling to connect evidence found in the
Ryugu samples to the potential underrepresentation of particular meteoritic constituents in terrestrial collections.

References[1] A. Yamagishi, S. Yokobori, K. Kobayashi, H. Mita, H. Yabuta, M. Tabata, M. Higashide, and H. Yano (2021)
Scientific Targets of Tanpopo: Astrobiology Exposure and Micrometeoroid Capture Experiments at the Japanese Experiment
Module Exposed Facility of the International Space Station, Astrobiology, p1451-1460. http://doi.org/10.1089/ast.2020.2426[2] S. Sasaki, J. Imani, and H. Yano (2019) Design, Fabrication and Evaluation of an Aerogel Processor CLOXS for the
Astrobiology Mission Tanpopo, Biological Sciences in Space, 33, p. 7-11.
[3] L. Pinault, K. Okudaira, H. Kiryu, I. Crawford, and H. Yano (2023, in preparation) Machine Learning Programme forExtraterrestrial Microparticles Using a Custom Machine Learning Model with Mobile Computer Vision and Processing
Systems, Journal title?
[4] M.J. Genge, N. Almeida, M. Van Ginneken, L. Pinault, P. Wozniakiewicz, and H. Yano (2023) Ice and Liquid Water inAsteroid Ryugu – Constraints from Sample A0180, this volume.

Characterization of Mg-Fe carbonates in the Ryugu returned samples with MicrOmega
Loizeau, D.1; Mahlke, M.1; Pilorget, C.1; Brunetto, R.1; Baklouti, D.1; Ito, M.2; Bibring, J.-P.1; Le Pivert-Jolivet, T.1;
Aléon-Toppani, A.1; Riu, L.3; Jiang, T.1,4; Hatakeda, K.5; Yogata, K.5; Nakato, A.5,6, Carter, J.1; Yada, T.5; Okada, T.5; Tahara,
R.5; Usui, T.5; Langevin, Y.1; Lantz, C.1; Tomioka, N.2; Yamaguchi, A.6; Uesugi, M.7; Miyazaki, A.5; Nishimura, M.5;
Nagashima, K.5; Kumagai, K.5; Hitomi, Y.5; Sugiyama, Y.5; Nakata, A.5
1
Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, France, 2Kochi Institute for Core Sample Research,
JAMSTEC, Japan, 3ESAC, ESA, Madrid, Spain, 4School of Earth Sciences, China University of Geosciences, Wuhan, China,
5Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan, 6National Institute of Polar
Research, Japan, 7JASRI/SPring-8, JapanThe Ryugu samples brought back by the Hayabusa2 spacecraft in December 2020 have been delivered to the JAXA
Extraterrestrial Curation Center [1]. Bulk samples and then sub-bulks and individual grains have been picked up and stored
into sapphire dishes, weighed, and analyzed with an optical microscope, FTIR spectroscopy, and MicrOmega hyperspectral
imaging [2] for initial description within the curation facility [1]. The MicrOmega instrument used in the JAXA Extraterrestrial
Curation Center is a NIR hyperspectral microscope. This configuration allows a mineralogical characterization of pristine
Ryugu samples, as they have never been exposed to terrestrial environment.
MicrOmega has a total field of view of 5 mm × 5 mm, with a resolution of ~22.5 µm/pixel in the focal plane. It covers the
spectral domain from 0.99 µm to ~3.6 µm. Its capabilities enable the identification of organic matter and different minerals in
the returned samples [3]. In particular, carbonates can be detected and characterized in the MicrOmega spectral domain
primarily through a strong absorption band at 3.3-3.5 µm, together with shallower specific bands at 2.5 and 2.3 µm, and forsome carbonates a large absorption band around 1 µm.
A recently published study [4] based on the analysis of MicrOmega data of ~180 extracted individual grains (a few mm insize) and 14 aggregate samples (all observed with MicrOmega within the Curation Center in 2021) has shown that carbonates
are distributed in two main populations. Those populations are different in composition and size/morphology: most detections
are made on small grains and inclusions (<100 µm large) with a spectrum similar to dolomite CaMg(CO₃)₂, while for thelargest detections, although less numerous, spectra similar to breunnerite (Mg,Fe)CO3 dominate.
Dolomite is present in many grains as inclusions, and in many aggregate samples, and many occurrences have been reported inrecently published studies analyzing some grains in detail [e.g., 5-11]. Breunnerite occurrences have been listed only in studies
accessing a larger volume of samples [e.g., 10-13]. However, the large size of breunnerite occurrences [4] makes them asignificant component of the returned Ryugu material, showing that it is important to understand when and how they formed
compared to the dolomite, and what was the source of Fe and C for this population of carbonates.
The largest breunnerite inclusion was found on grain C0041, covering ~0.25 mm², or ~10% of the visible surface of the grain.
This grain is one of the grains with “White regions” described in [5]. This carbonate inclusion shows a complex morphology
with three branches, 100s µm long, around a main area, that could point to a formation in a fracture or between grains. In
addition, several detached grains of breunnerite, 100s µm long, have been detected in several aggregate samples, indicating
possibly many other large inclusions from which those grains were separated.
MicrOmega did not detect any obvious spatial transition from dolomite to breunnerite within a carbonate detection at thesurface of grains, which would have indicated a possible gradient during a single formation event, although one observation of
dolomite in contact with breunnerite has been made through SEM observations [10]. To better understand formation processes,
we are investigating spatial heterogeneity of carbonate composition with a more systematic technique at small scale (few 10sµm) in the MicrOmega data to check for gradients in Mg or Fe content for example: to achieve this, we check for shifts in NIR
absorption band positions and shapes at the MicrOmega pixel level. We have also succeeded in extracting one loose grain ofbreunnerite (in collaboration with the Phase 2 curation Kochi team) and studying it with different techniques (imaging IR
spectroscopy, Raman spectroscopy, EDS) that will enable us to check for heterogeneities in carbonate composition of the grain
or the presence of other minerals or molecules within the grain at a smaller scale (<10 µm).
The two main populations of carbonates question the formation process or processes that occurred on Ryugu’s parent
body/bodies, and their respective age of formation. To our knowledge, only one attempt of Ryugu’s breunnerite dating has
been published so far [6] that does not conclude on a noticeable difference in age of formation between breunnerite anddolomite. More studies of breunnerite occurrences are required to better constrain their age, formation, and carbon sources.

References[1] Yada T. et al. (2021) Nature Astronomy 6, p.214-220. [2] Pilorget C. et al. (2021) Nature Astronomy 6, p.221-225. [3]
Pilorget C. and Bibring J.-P. (2014) PSS 99, 7-18. [4] Loizeau D. et al., (2023) Nature Astronomy 7, 391-397. [5] Nakato A. et
al. (2023) Earth, Planets and Space, 75(1), 45. [6] McCain K. A. et al. (2023) Nature Astronomy, 7(3), 309-317. [7] Fujiya W.
et al. (2023). Nature Geoscience 16, 675-682. [8] Dartois E., et al. (2023) Astronomy & Astrophysics, 671, A2. [9] Nakamura
E. et al. (2022) Proceedings of the Japan Academy, Series B, 98(6), 227-282. [10] Yamaguchi, A., et al. (2023) Nature
Astronomy, 7(4), 398-405. [11] Ito, M., Tomioka, N., Uesugi, M. et al. (2022) Nat Astron 6, 1163–1171. [12] Yokoyama T.
(2022) Science, 379(6634), eabn7850. [13] Nakamura T. (2022) Science, 379(6634), eabn8671.

Heterogeneity of Ryugu samples due to space weathering effects: near-infrared spectroscopy andfitting analysis
S. Furukawa1,2, T. Okada1,2, K. Yogata2, K. Hatakeda2,3, T. Yada2, A. Miyazaki2, K. Nagashima2, R. Tahara2, Y. Sugiyama2, A.
Nakano2, T. Ojima2, Y. Hitomi2,3, K. Kumagai2,3, M. Nishimura2, M. Abe2, T. Usui2, J.-P. Bibring4, C. Pilorget4, V. Hamm4, R.
Brunetto4, D. Loizeau4, L. Riu4, T. Le Pivert-Jolivet4,
1
University of Tokyo, Japan, 2Institute of Space and Astronautical Science, JAXA, Japan, 3Marine Works Japan, Yokosuka,
Japan, 4Institut d'Astrophysique Spatiale, Universite Paris-Saclay, Orsay, France.
Introduction
Hayabusa2 brought back about 5.4 g of Ryugu samples (chamber A: surface samples, chamber C: excavated samples)from the C-type asteroid Ryugu in 2020, and the initial description of the returned samples is ongoing at the Curation Center of
the Institute of Space and Astronautical Science (ISAS), JAXA [1][2]. In the initial description, measurements with a nearinfrared hyperspectral microscope MicrOmega and spectral analysis are ongoing, and we have developed a fitting analysis
method for the asymmetric absorption bands [3].
MicrOmega is a near-infrared hyperspectral microscope developed by the Institut d’Astrophysique Spatiale (IAS) in
France, characterized by its ability to acquire spectral data over an area of approximately 5 mm square with a resolution of 22.5µm/pix at 0.99-3.65 µm [4]. The measurement results to date have indicated a relatively deep absorption band at 2.7 µm whichis thought to originate from the OH group and a slope around 2.0 µm, as common features of most of the Ryugu samples [2].
Methods
In our previous work [3], we developed a fitting analysis method with four Gaussian functions to achieve a more physicallyaccurate analysis for the characteristic 2.7 µm asymmetric absorption band of Ryugu samples. In this study, we applied a fitting
analysis with six Gaussian functions after applying baseline estimation and smoothing where necessary [5]. We also applied afitting analysis with linear functions to the slope around 2.0 µm, which is a characteristic of Ryugu samples, to determine themagnitude of the slope [6].
The spectroscopic data were used in the MicrOmega-Curation DARTS Server (chamber A: 95 spectra, chamber C: 62
spectra).
Results
The results of the fitting analysis are shown in Figure 1 (left) with each Gaussian function, composite waveform, andresiduals for the asymmetric absorption band of Ryugu sample A0007 at 2.7 µm. Each of the six Gaussian functions is named
f1 to f6 from the short wavelength side, where their peak wavelengths are f1: 2.713 µm, f2: 2.748 µm, f3: 2.786 µm, f4: 2.831µm, f5: 2.874 µm, and f6: 3.036 µm, respectively.
The results of the fitting analysis using linear functions are shown in Figure 1 (right) for the slope around 2.0 µm.

f4 f5
f3

f6

f2
f1

[Figure 1: Results of fitting analysis of spectral data measured by MicrOmega with Ryugu sample A0007 (left: fitting analysis by six Gaussianfunctions for the asymmetric absorption band at 2.7 µm, right: fitting analysis by linear functions for the slope around 2.0 µm)]

Discussion
The relationship between peak wavelength and depth of the 2.7 μm absorption band (Figure 2 left) shows that the chamber
A sample is split into two groups: α, with a shorter peak wavelength and greater depth, and β, with a longer peak wavelengthand smaller depth. In contrast, the chamber C sample does not exhibit a clear tendency for such division into two. Thisdichotomous distribution for the chamber A sample is also present for f1, f2, and f4. Therefore, f1, f2, and f4 are considered to
be derived from the same functional OH group. On the other hand, f3, f5, and f6, which do not exhibit dichotomous distribution
in the chamber A sample, may be derived from carbonate, carbonyl, and NH groups, respectively, based on the position of thepeak wavelengths [2][4][8].
Based on the results of the slope analysis around 2.0 µm, β tends to have a larger absolute value of slope than α, despite
within the standard error range, as shown in Figure 2 right (α: (1.79 ± 0.501) x 10-4 [%/cm-1], β: (1.84 ± 0.576) x 10-4 [%/cm-1],
C: (1.81 ± 0.496) x 10-4 [%/cm-1]). Since the slope of the spectrum is considered to reflect the effect of space weathering, β may
be affected by greater space weathering than α [9].
Therefore, in the relationship between peak wavelength and depth in the 2.7 μm absorption band (Figure 2 left), the longer
wavelength and smaller depth of the peak position for β compared to α may be due to the greater effect of bond scission related
to the OH group caused by space weathering.
In summary, the Ryugu return samples that were measured by MicrOmega were classified into three major groups: α andβ in chamber A, and C in chamber C. Also, each of them is considered to be affected by greater space weathering in the order of
α < C < β, respectively.

[Figure 2: Left: Relationship between peak wavelength and depth of the composite waveform in the 2.7 µm absorption band, right: slope
magnitude around 2.0 µm (chamber A sample: α and β only) versus Frequency ratio]

References[1] Yada, T. et al. 2021. Nature Astronomy 6:214.
[2] Pilorget, C. et al. 2021. Nature Astronomy 6:221.
[3] Furukawa, S. et al. 2023. Abstract #PPS03-10. JpGU2023.
[4] Bibring, J.-P. et al. 2017. Space Science Reviews 208:401.
[5] Eilers, P. H. C. & Boelens, H. F. M. 2005. Leiden University Medical Center report 1:5.
[6] Furukawa, S. et al. 2023. Abstract #OA-06. JSPS2023 (in Japanese).
[7] Le Pivert-Jolivet, T. et al. 2022. Abstract #6255. MetSoc2022.
[8] Loizeau, D. et al. 2023. Nature Astronomy 7:391.
[9] Morota, T. et al. 2020. Science 368:654.

NH-rich grains detected by MicrOmega in the Ryugu returned samples
Jiang T.1,2, Pilorget C.1, Loizeau D.1, Bibring J.-P.1, Yogata K.3, Hatakeda K.3,4, Brunetto R.1, Le Pivert-Jolivert T.1, Lantz C.1,
Riu, L.1,5, Yada T.3, Okada T.3,6
1
IAS, Université Paris-Saclay, CNRS, France, 2School of Earth Sciences, China University of Geosciences, Wuhan, China,
3
ISAS Sagamihara Japan,4Marine Works Japan, Ltd, Yokosuka Japan, 5ESAC, ESA, Madrid, Spain,
6
University of Tokyo, Tokyo, Japan
NH-rich compounds have been reported on Ceres [1, 2], Comet 67P [3, 4], and other primitive asteroids [5, 6] thanks to NIR
observations. The proposed compositions include ammonium salts, ammoniated phyllosilicates, and ammonia-bearing organics.
Investigating their composition and relation with other components can tell us information on how they were formed, what was
the environment, and may also indicate the transfer of some volatiles in the Solar System. Similarly, NIR observations of the
Ryugu samples obtained at the millimeter scale showed that they exhibit a ~3.06 µm shallow feature that was tentatively
attributed to NH-rich compounds that would be present at a small scale and spread over the collection [7, 8]. However, one
grain (a few hundred microns in size) exhibited a much stronger ~3.06 µm feature, coupled with additional features such as~3.24 µm and ~2.72 µm bands [7]. Its reflectance (~10%) was also much higher than that of the typical matrix (2-3%). Here
we report on our latest analyses to identify grains/inclusions with similar properties (both showing 2.7 µm and 3.06 µm
absorptions).
MicrOmega is an infrared hyperspectral microscope installed inside the Hayabusa2 Curation Facility. It covers the spectral
range 0.99-3.65 μm with a pixel size of ~22.5×22.5 µm², and a total field of view covering ~5×5 mm². From 2021 to July 2023,
MicrOmega has measured almost half (in weight) of the Ryugu returned samples in the form of aggregates (~50) (small
subsets extracted from the bulks, a few tens of mg each) and individual (mm-sized) grains (>500). Here we focus on theaggregate samples, which give access to a large number of grains spread as a thin layer in the sample holders. We use theaverage spectrum of the grain from the first NH-rich detection in [7] as a reference. After removing the continuum from 2.5 to
3.2 μm, we calculate the similarities between the reference spectrum and spectra from each pixel, then select the enriched
regions with high similarity (strong 3.06 μm and 2.7 µm bands) and check for consistency at different orientations to avoid
biases.
The detections of such areas are quite rare: among all the aggregate samples, we have detected 10 regions of interest (ROIs).
The reflectance of the ROIs is generally higher than that of the surrounding material, mostly ranging from ~5% to ~10% but
can be up to 15%. The size of the ROIs varies from ~100 μm to ~400 μm, their shape can be from relatively rounded toelongated. Figure 1 shows an RGB image (R 2.01 μm, G 2.72 μm, B 3.45 μm) of an aggregate sample, the pink color area is
the ROI, and its average spectrum shows very strong 2.7 μm absorption (~50%) and 3.06 µm feature (~10%). We will reporton the spectral heterogeneity within the ROIs at pixel scale and between different ROIs, in particular their variations in band
position, depth, and shape. Since most of the ROI are present as inclusions instead of isolated grains, we will also present theirrelationship with the surrounding materials.
Such detections highlight the presence of a few particular grains in the
Ryugu returned samples that may contribute to understanding the origin
and evolution of the N-bearing material in Ryugu’s parent body.
Figure 1. RGB image of an aggregate-sample (Sample ID: A0481). R 2.01 μm, G2.72 μm, B 3.45 μm. The pink region pointed by the yellow arrow is the NH-rich
ROI.

References [1] King et al., 1992. Science 255, 1551-1553. [2] De Sanctis
et al., 2015. Nature. 528, 241-244. [3] Poch et al., 2020. Science. 367
eaaw7462. [4] Raponi et al., 2020. Nature Astronomy. 4, 500-505. [5]Takir and Emery 2012. Icarus. 219, 641-654. [6] Rivikin et al., 2022.
Planetary Science Journal. 3.153 [7] Pilorget et al., 2022. Nature
Astronomy. 6, 221-225. [8] Yada et al., 2022. Nature Astronomy. 6, 214220.

Nanoscale spectroscopic and microscopic investigation of Ryugu samples
Mehmet Yesiltas1, Timothy D. Glotch2, Yoko Kebukawa3, Paul Northrup2, Bogdan Sava4, Yasin Durmaz4
1

Kirklareli University. Turkey, 2Stony Brook University, USA, 3Tokyo Institute of Technology, Japan, 4Attocube Systems,
Germany

Carbonaceous asteroids are leftover materials from the early solar system. Having escaped harsh planetary processes, they
provide clues to understanding the planet formation processes as well as the origin and evolution of the early solar system. The
Hayabusa2 spacecraft returned the first samples from the carbonaceous asteroid Ryugu [1,2]. In addition to abundantphyllosilicates (~64–88 vol%;), carbonates, sulfides, and magnetite [3], the returned samples provide uncontaminated pristineorganic compositions Macromolecular insoluble [4] and soluble organic matter as well as presolar silicate grains [6,7] havebeen reported in the Ryugu particles. Extraterrestrial organic matter is typically submicron in size (50-500 nm), and mostorganic compounds are even smaller [8,9]. Conventional IR methods fail to detect spectral signatures of nanoscale organic
matter in extraterrestrial samples because of their insufficient spatial resolutions and other technical limitations.
In this study, we investigated the mineralogy and organic matter content of two Ryugu particles, A0030 (from TD1, chamberA) and C0034 (from TD2, Chamber C), using scattering-type near-field optical microscopy (s-SNOM)-based nanoscale
Fourier transform infrared (nano-FTIR) spectroscopy, pseudoheterodyne (PsHet) nanoscale imaging, micro-Raman
spectroscopic imaging, and synchrotron-based X-ray microprobe analyses.
Our results show that the two Ryugu particles contain different silicate minerals and organic-rich compositions. The spatial
distributions of chemical functional groups and their relations with other components also differ in the studied Ryugu particles.
Our results indicate various stages of aqueous alteration and thermal metamorphism processes for Ryugu. The identification ofabundant nanoscale organic molecules within the Ryugu grains that could not be identified via micrometer-scale investigations
emphasizes the importance of using nanoscale nondestructive methods for studying primitive solar system materials, such as
Ryugu particles and those that will be returned soon (such as OSIRIS-REx and MMX samples).

References[1] Tachibana et al. 2022. Science 375, 1011–1016. [2] Yada et al. 2022. Nat Astron 6:214–220. [3] Ito et al. 2022. Nat.
Astron. 6:1163–1171. [4] Yabuta et al. 2023. Science 379, eabn9057. [5] Naraoka et al. 2023. Science, 379, eabn9033. [6]Barosch et al. 2022. The Astrophysical Journal Letters, 935,1. [7] Nguyen et al. 2023. Science Advances, 9(28), eadh1003. [8]Garvie et al. 2008. Meteoritics & Planetary Science 43, 899-903. [9] Yesiltas et al. 2021. Scientific Reports 11, 11656.

Spectroscopic Evidence of Parent Body Aqueous Alteration on Ryugu Sample A0112
A. Maturilli1, E. Bonato1,2, J. Helbert1, G. Alemanno1, Van den Neucker1, S. Schwinger1, M. Baqué1, M. Hamm3, M.
D’Amore1, C. Hamann2, K. Mahlow2, M. Patzschke3, A. Greshake2, L. Hecht2,31German Aerospace Center (DLR) – Institute of Planetary Research, Rutherfordstrasse 2, 12489 Berlin, Germany,
2Museum für Naturkunde - Invalidenstraße 43, 10115 Berlin, Germany,
3Freie Universität Berlin – FB Geowissenschaften – Institut für Geologische Wissenschaften Planetologie andFernerkundung – Malteserstr. 74 – 100 – 12249 Berlin, Germany.
The Japanese Hayabusa2 sample return mission successfully retrieved fragments from the near-Earth C-type
carbonaceous asteroid Ryugu (162173). These fragments share similarities in composition with the Ivuna meteorite,
indicating a potential classification as a primitive CI-type asteroid [1]. Among the collected samples, the piece A0112
was sent for spectral analyses at the Planetary Spectroscopy Laboratories (PSL) at the German Aerospace Center(DLR) in Berlin.
The A0112 piece is a relatively large sample collected from the first touchdown site [1]: it weighs 5,1 mg and is3046x1823 µm in size. The sample was contained in a nitrogen-filled sample holder, free of any form of terrestrial
contamination after its retrieval from the asteroid. In order to preserve the sample from external contamination, suchas the atmosphere, the first set of analyses were performed with the grain sealed within its sample holder. These
analyses employed micro-infrared spectroscopy and Raman micro-spectroscopy. In addition, High-resolution 3D
images were taken of multiple sides of the grain with the digital microscope Keyence VHX-7000 and VHX-7100
observation system, which allowed a global view of its surface morphology and topography. This approach enabled
the determination of the sample's bulk composition and mineralogy beneath the glass without being influenced byterrestrial alteration.
More than 50 point-localized infrared spectroscopy measurements were performed on the A0112 grain with theHyperspectral Bruker Hyperion 2000 MicroFTIR to assess the general mineralogy of the fragment through the glass
window of the sample holder. MIR (1.3 – 5 µm) reflectance point measurements consisted of 1000-2000 scans at an
optical magnification of 15x and a resolution of 4 cm-1. VNIR reflectance spectra were also taken to cover the full
spectral range. Raman spectroscopy under neutral atmosphere with the WiTec Alpha 300 confocal Raman microscope[2] was used for organic matter and mineral identification, and to generate elemental maps of the grain.
Through the use of FTIR spectrometers (three identical Bruker Vertex 80V) and a special manufactured sample holder
it was possible to measure bi-directional reflectance bulk sample spectroscopy of sample A0112 completely undervacuum in the whole spectral range from UV to FIR (0.25 µm to at least 25 µm spectral range).
From the processed images, the sample can be described as a mostly dark fragment with a few micron-sized, brightinclusions on most of its faces. Micro-FTIR measurements revealed an abundant presence of secondary minerals suchas phyllosilicates throughout the sample, with a localized area of approximately 30 µm rich in carbonates. This
carbonate-rich region was identified as dolomite due to specific absorbance bands at wavelengths of 1.90, 2.21, 2.73,
and 4.4 µm, as well as two distinctive sets of doublets at 3.33, 3.47 µm and 3.81, 3.95 µm [1, 3]. Raman spectroscopy
measurements also confirmed the presence of dolomite with spectral bands at 175, 300, 727, and 1098 cm-1. This
dolomite inclusion appears to be associated with a vein in the grain. The investigation of hydrated minerals formed
through aqueous alteration on the parent body provides valuable insights into the evolution of materials characterizing
Ryugu and the protoplanetary disk. The presence of carbonates is particularly significant, suggesting the presence ofliquid water within the asteroid, which could potentially play a role in delivering water to Earth or other planets [4].
Furthermore, these results confirm that in-situ point measurements, to localize hydrated minerals and organic matter,are still achievable through the glass window of a sample holder.
The identification of carbonates in the sample provides significant evidence of aqueous alteration processes that
occurred on Ryugu's parent body.
References[1] Nakamura, T. et al. (2022) Science. [2] Böttger, U. et al. (2013) LPS XVIV, Abstract #2092. [3] Loizeau, D., et al.
(2023) Nat Astron. 7, 391-397. [4] Ito, M. et al. (2022) Nat. Astron. 6, 1-9.
Acknowledgements
The research results have been obtained through the cooperation between DLR and JAXA.

Nitrogen, neon, and argon analysis of a single Ryugu grain by step-heating
J. Gamblin1, E. Füri1, B. Marty1, L. Zimmermann1, D.V. Bekaert1, and M.W. Broadley1
1
Université de Lorraine, CNRS, CRPG, Nancy, France
Introduction: Carbonaceous chondrites are primitive, volatile-rich meteorites, considered to originate from C-type asteroids,
which may have contributed to Earth’s volatile budget. Studying these objects is key to understand the origin of Earth’s
volatiles, but terrestrial weathering makes it difficult to distinguish between primary and secondary features. In December
2020, JAXA’s Hayabusa2 mission returned to Earth 5.4 g of regolith collected on the C-type asteroid (162173) Ryugu,
permitting the analysis of material not altered by terrestrial weathering [1]. The first analyses of noble gases and nitrogen were
performed by the ‘initial analysis volatile team’ [2-3], providing key information about Ryugu, especially its formation,
composition, and alteration history. Noble gases were found to be mainly of primordial and presolar origin, with variable
contributions from solar wind and cosmogenic components. Nitrogen was present in lower abundances (700 to 900 ppm [2-3])
than in typical CI chondrites, with ẟ15N values ranging from 0.0±0.4 ‰ [2] up to +43±4 ‰ [4], indicating sample
heterogeneity and the presence of at least two carrier phases: a N-rich phase with ẟ15N up to +70 ‰ and a N-depleted phasewith ẟ15N near 0 ‰.
Sample and experimental method: For this study, we targeted grain A-0164 (2.6 mg), which was sampled during the first
touchdown on the asteroid and corresponds to surface material. The grain was analyzed at the Centre de Recherches
Pétrographiques et Géochimiques (CRPG, Nancy, France) by step-heating with a CO2 laser. By performing a large number ofextraction steps, various components of nitrogen and noble gases, carried by different phases, can be distinguished. A total of
85 heating steps were performed at increasing laser power to successively analyze the different phases carrying nitrogen andnoble gases. Nitrogen, neon, and argon abundances and isotope ratios were analyzed at each step using a Nu Instruments
Noblesse HR mass spectrometer, a state-of-the-art instrument for multi-collection, high-precision, static-vacuum analysis.
Preliminary results:
Noble gases. Neon was mainly released at low temperature steps, whereas Ar was extracted over a wide temperature range.
The sample presents a mainly solar wind-like isotopic composition for noble gases, as shown for neon in Figure 1. Step
heating allowed us to identify other components, including primordial and presolar components (possibly phase Q and/or HL),as well as a minor cosmogenic contribution.
Nitrogen. Nitrogen is present in higher abundance (1219±113 ppm) than in previous studies, with a bulk ẟ15N value of+24.4±0.1 ‰, with significant variations during successive extractions (+1.0±1.0 ‰ to +65.8±1.1 ‰), pointing to the presenceof at least four N-carrier phases.

Figure 1.

Ne (20Ne/22Ne) isotope ratio (colored circles) and 20Ne abundance (gray histogram) measured for each of the 85 extraction steps

at increasing laser power. The Ne isotopic compositions of the solar wind, Phase Q, and Ne-HL are shown for comparison.

References[1] Tsuda Y. et al. 2020. Acta Astronautica 171 42:54. [2] Okazaki R. et al. 2023. Science 379 6634. [3] Broadley M.W. et al.
2023. Geochemica et Cosmochimica Acta 345 62:74. [4] Yabuta H. et al. 2023. Science 379 6634.

Chemical composition and variability of Ryugu samples, CI chondrites and Kainsaz assessed byquadrupole ICP-MS analyses
Frank Wombacher
Institute of Geology and Mineralogy, Universität zu Köln, 50674 Köln, Germany.
Introduction. The similar relative abundances of non-atmophile elements between the Sun and rare CI chondrites suggest that
CI chondrites represent the most primordial meteorites available for laboratory analyses. Samples returned from asteroid
Ryugu by the Japanese Hayabusa2 mission resemble CI chondrites, were not altered on Earth, but affected by aqueousalteration [1-4].
This study aims to provide additional data on the elemental compositions and variabilities and representative sample masses
for CI chondrites, Ryugu and the Kainsaz CO3 chondrite.
Samples. Data was obtained for five ~3 mg Ryugu samples from chamber A (1st touchdown), seven ~3 mg chips and 3, 4 and
50 mg bulk powder samples from the Kainsaz CO3 chondrite and ~50 mg powder aliquots from the CI chondrites Ivuna (2 x),
Orgueil (3 x) and Y-980115. For quality control, Allende Smithsonian reference powder, JB-2, BHVO-2 and ~3 mg powder
test samples from Allende, Ivuna, JB-2 as well as a Perkin Elmer multi element solution were analyzed.
Methods. The ~3 mg samples were digested in HF-HNO3 at hotplates. The Ryugu samples and 5 out of 7 chips from Kainsaz
were not ground before digestion to avoid material loss. Most 50 mg samples were digested in Parr pressure digestion vessels.
Methods for quadrupole ICP-MS analyses and data evaluation are given in [5]. Samples were 4000-fold diluted and Rh and Re
were used as internal standards. Most elements were determined in kinetic energy discrimination mode using He as a cell gas
with CeO/Ce ~ 0.4%. (1.7% in standard mode). For each sample set, three to seven measurement sessions were run. Outliers
were removed if > 4 sd and Ta data was rejected from four sessions that yielded unusual low Ta values. Four-point matrix
matched calibration [5, 6] yielded a median correlation coefficient of 0.9999 as calculated from all elements and sessions.
Repeatability judged from 121 analyses of Ivuna was 3.2% on average with Mn, Co, Cu, Rb, Y, Sr, Pb < 1.5% and 23% for Be
being the worst case. In order to rigorously control blank contributions, seven blanks each were prepared along with the Ryugu
and Kainsaz samples and four blanks with the 50 mg CI chondrite samples. Median blanks were subtracted. Maximum blanks
for ~3 mg samples were: Ryugu and Ivuna: As, Sn and Sb 2 to 6%; Nb 10%; W 16%; Mo 29%; Kainsaz: Zn, As, Cd and Sn<3%; W 15%; JB-2: Zn, Nb, Sn and W 5 to 6 %; Mo 35%.
Results. Most CI chondrite, Allende Smithsonian, JB-2, BHVO-2 and Perkin Elmer solution data agrees within 10 to 20% withreference data [e.g., 7-13]. However, due to problems related to the calibration solutions (as observed in [6]), Sr, Mo, Sb, Ho,
Ta, W and Bi are systematically too low. For the basalt reference samples, S, Se, Ag, Ir and Pt were not quantified and Ti, Cr,
Ni, Te and As are off by about 20 to 60%. Except for U in Ivuna, results for 3 mg test samples agreed with results for thecorresponding 50 mg samples to within better than 10% or within 10 to 20% for Se, Ag, Te (Ivuna), S, Ag, Ir, Pt (Allende) andAs and Bi for JB-2 (S, Se, Ag, Ir and Pt not quantified in basalt reference materials). Three mg chips from Kainsaz display
some heterogeneity and scatter around the data for the 50 mg bulk sample. However, the 50 mg bulk sample and 3 and 4 mg
aliquots from the same powder display fractionated REE. The REE Kainsaz data shows that nugget effects in chondrites canaffect larger samples more significantly than small mg samples. The Kainsaz 3 mg chip data displays reproducible, sometimes
large enrichments in As, Sb and Pb of unknown origin.
Discussion. Ivuna and Mg normalized data reveal the following: Many elements in CI chondrites agree within ~2 %. Two outof three Orgueil samples display 20 to 50% enrichments in some refractory elements, most notably Zr, Hf, Th and Ba while Y980115 is depleted in Cd, In, Tl and Bi as observed previously [5]. One Ryugu sample matches the CI chondrite REE pattern,
the other four samples are enriched in light over heavy REE with variable REE/Mg. Two Ryugu samples are clearly enrichedin Ca and Sr, one in Mn and Fe. Only one out of five Ryugu samples displays contamination of Ta from the projectile. Overall,the 3 mg Ryugu samples from chamber A display a clear CI chondrite affinity, but their chemical compositions are obviously
affected by aqueous alteration as previously observed. For CI chondrites, Kainsaz and Ryugu, we estimated the representative
sample mass needed to obtain elemental abundances to within 5% at the 95% confidence level, using the formula given in[10]: Representative sample mass = test portion mass * (standard deviation / (mean * standard error of the mean))2 * student-t
distribution factor.
For CI chondrites (n=4), the median representative sample mass corresponds to 452 mg; for ten elements, including Na, Zr, Hf,
Ba, La, Ce and U, the representative sample mass was above 1 g. For Kainsaz, the median representative sample mass equals
74 mg and is above 1 g for S, As, Cd, Sb, Cs and Pb only. The median representative sample mass calculated for Ryugu

corresponds to 99 mg with Mn, Ca and P being the least homogeneous elements with calculated representative sample massesof about 300, 400 and 500 mg. A complete table can be obtained from the author.
Acknowledgements
JAXA for sampling Ryugu and the incredible opportunity to work on these samples. The National Institute of Polar Research(Naoya Imae) for Y-980115, the Smithsonian Institution (Tim McCoy and Glenn MacPherson) for the Allende reference
powder, the NHM London (Helena Bates, Natasha Almeida) for Ivuna and Orgueil, the MNHM in Paris (Matthieu Gounelle)
and the Universität Münster (Addi Bischoff) for Orgueil. Carsten Münker for lab use; Claudia Funk and Ninja Braukmüller forsupport in the lab.
References[1] Yokoyama T. et al. (2022) Science 379, [2] Nakamura T. et al. (2022) Science, 379, [3] Ito M. et al. (2022) Nature
Astronomy 6, 1163–1171, [4] Greenwood R. et al. (2023) Nature Astronomy 7, 29-38, [5] Bates H. C. et al. (2023) Meteoritics& Planetary Science. [6] Braukmüller N. et al. (2018) Geochimica et Cosmochimica Acta 239, 17–48, [7] Lodders K. (2021)
Space Science Reviews 217, 44, [8] Barrat J.A. et al. (2012) Geochimica et Cosmochimica Acta 83, 79-92, [9] Jarosewich E.
et al. (1987) Smithsonian Contributions to the Earth Sciences 27, 49, [10] Stracke A. et al. (2012) Geochimica et
Cosmochimica Acta 85, 114–141, [11] Wang Z. and Becker H. (2014) Geostandards and Geoanalytical Research 38, 189–209,[12] Jochum K. P. et al. (2005) Geostandards and Geoanalytical Research 29, 333–338, [13] Braukmüller N. et al. (2020)
Geostandards and Geoanalytical Research 44, 733–752.

The Mineralogy of Asteroid Ryugu and its
Relationship to Highly Altered Extraterrestrial Materials
Ashley King1, Sara Russell1, Martin Suttle2, Catherine Harrison1,
Paul Schofield1, Helena Bates1, and the Hayabusa2 “Stone” team
1
Natural History Museum, London, UK (a.king@nhm.ac.uk)
2
The Open University, Milton Keynes, UK
The Hayabusa2 mission returned to Earth with ~5.4 g of material collected from two sites on the surface of the Cb-type
asteroid (162173) Ryugu [e.g., 1]. In hand specimen, Ryugu particles are dark, often highly friable, and have bulk densities in
the range of ~1.2 – 1.8 gcm-3 [2–4]. Most Ryugu particles examined to date are breccias consisting of an abundant (~80 – 90
vol.%) fine-grained (<1 μm) matrix of phyllosilicates (interlayered serpentine and saponite) in which coarser (~10’s – 100’s
μm in size) grains, fragments, and clusters of oxides (~4 vol.%), sulphides (~3 vol.%), carbonates (~3 vol.%), and phosphates(<1 vol.%) are embedded [2–6]. Several CAI-like fragments (<30 μm) have been identified, as have small (<10 μm), rounded
objects with characteristics, such as barred textures, related to melting and crystallisation in chondrules [e.g., 4, 7]. The
mineralogy, petrography, and physical properties of Ryugu particles are consistent with them being having formed throughnear-complete, low temperature (<50°C) water-rock reactions during the first few million years of the Solar System [2–6].
If samples of Ryugu were to land on Earth as meteorites, we could classify them as petrologic type 1 [8]. Such materials werecompletely altered to secondary mineral assemblages by aqueous processing and contain various phyllosilicates, carbonates,
sulphides, and magnetite. Type 1 materials are represented in four meteorite groups (CI, CM, CR, and CY), a handful of
ungrouped chondrites (e.g., Flensburg [9]), as xenoliths within meteorites [e.g., 10], and as fine-grained micrometeorites [e.g.,
11] and interplanetary dust particles (IDPs) [e.g., 12]. The mineralogy and chemistry of Ryugu particles are closely related to
the CI1 (“Ivuna-like”) carbonaceous chondrites, except for the presence of sulphates and ferrihydrite in the latter, which aremost likely terrestrial weathering products [13, 14]. However, type 1 samples exhibit a remarkably high diversity of starting
materials and alteration conditions, with variations in mineralogy, textures, and oxygen isotopic compositions pointing towards
multiple parent bodies. Despite type 1 materials being relatively rare in our collections, in part due to their fragile naturehindering survival during atmospheric entry, highly altered bodies appear to be common throughout the Solar System. Thesebodies could include primitive asteroids that accreted within the inner and/or outer Solar System, or transition objects such as
Main Belt comets or D-type asteroids. Characterising the sources of type 1 materials through laboratory analysis of meteorites
and Ryugu particles is therefore an important step towards understanding volatile reservoirs in the early Solar System.
References[1] Yada T. et al. 2021. Nature Astronomy 6:214. [2] Yokoyama T. et al. 2022. Science 379:abn7850 [3] Nakamura E. et al.
2022. Proc. Jpn. Acad., Ser. B 98:227. [4] Nakamura T. et al. 2022. Science 379:abn8671 [5] Ito M. et al. 2022. Nature
Astronomy 6:1163. [6] McCain K. et al. 2023. Nature Astronomy 7:309. [7] Liu M-C. et al. 2022. Nature Astronomy 6:1172.
[8] Russell S. et al. 2022. Meteoritics and Planetary Science 57:277. [9] Bischoff A. et al. 2021. Geochimica et Cosmochimica
Acta 293:142. [10] Zolensky M. et al. 1996. Meteoritics and Planetary Science 31:484. [11] Kurat G. et al. 1992. 27th LPSC
#747-8. [12] Aléon J. et al. 2009. Geochimica et Cosmochimica Acta 73:4558. [13] Gounelle M. & Zolensky M. 2001.
Meteoritics and Planetary Science 36:1321. [14] King A. et al. 2020. Geochimica et Cosmochimica Acta 268:73.

Paleomagnetic Evidence for Formation of Ryugu in the Distal Solar System
Elias N. Mansbach1, Eduardo A. Lima1, Michael Sowell2, Joseph L. Kirschvink2, Jodie B. Ream1, Roger R. Fu3, Saverio
Cambioni1, Xue-ning Bai4, Benjamin P. Weiss1
1

Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology; Cambridge, MA,USA.
2

Division of Geological and Planetary Sciences, California Institute of Technology; Pasadena, CA, USA
3

Department of Earth and Planetary Sciences, Harvard University; Cambridge, MA, USA

4

Institute for Advanced Study and Department of Astronomy, Tsinghua University; Beijing, China

Paleomagnetic studies of meteorites have demonstrated that the solar nebula generated a magnetic field that likely played an
important role in accretion during the early solar system [1]. The nebular field reached intensities of 54 ± 21 µT at heliocentric
distances of 1-3 AU [2] and 101 ± 48 µT at 3-7 AU [3], and likely decayed by ~3-4 million years (Ma) after the formation of
calcium aluminum-rich inclusions (CAIs) [4-7]. However, with the possible exception of Tagish Lake and Wisconsin Range(WIS) 91600, these studies have been restricted to meteorites that formed at distances <7 AU [8, 9]. Tagish Lake is of particularinterest as its arrival to Earth from the asteroid belt implies that its parent body had been inwardly scattered, perhaps due to theformation and migration of the giant planets [9, 10].
The returned samples from asteroid (162173) Ryugu
by the Hayabusa2 mission currently provide the best
opportunity to study the nebular field in the distal solar system
as the parent body may have experienced aqueous alteration at
distances up to ~20 AU [11]. These particles are also highquality targets for paleomagnetic investigations as they are: 1)
in pristine condition since careful sample handling limits thepossibility of magnetic and terrestrial contamination, which
can lead to the creation of ferromagnetic minerals that mask
the primary record of the particles, and 2) contain single-vortex
framboidal magnetite which can retain magnetic records over
the age of the solar system [12]. If the magnetite shows
evidence of magnetization produced by an ancient field, thesource of the field could have been the nebular field or a
dynamo on the parent body. The latter case is of particularinterest since this would imply that the parent body was
Figure 1: Orthographic projection of endpoints of NRM vectors on
partially differentiated with a carbonaceous chondritic crust
the northeast (N-E) and up-east (Z-E) planes during alternating fielddemagnetization of particle A0397. The LC component is shown in[13]. Our current understanding of the lifetime of the nebula
red, the MC component in blue, and the HC range in black. No
suggests that if the natural remanent magnetization (NRM)
components are observed >24 mT.
was acquired < 4 Ma, the source of the field was the nebula
while a younger age would be indicative of a parent body dynamo. Initial Mn-Cr dating on carbonates that are thought to haveformed at the same time as the magnetite yielded an age of 3.1 – 6.8 Ma after the formation of CAIs [14], but more recent datingon carbonates using the same dating system and improved calibrations suggests alteration occurred < 1.8 Ma after CAI formation[15].
An initial paleomagnetic study of two Ryugu particles concluded that the particles formed in a > ~40 - 400 µT nebular
field [14, 16]. However, this magnetization may be post-sampling contamination because: 1) magnetite can have coercivities up
to 300 mT, but the NRMs of previously studied samples were unblocked to only 30 mT; 2) the previously studied samples had
been analyzed with an electron microprobe which may have imparted a weak isothermal remanent magnetization (IRM); and 3)
initial analysis of MasMag magnetometer data suggested that a boulder on Ryugu did not possess a measurable magnetization(< 3 × 10-6Am2 kg-1 at the m-scale) [17], yet the moment per unit mass of the reported samples is well above this limit (2.14 ×
10-5 Am2 kg-1).

To address the origin and nature of NRM in Ryugu, we
conducted an additional paleomagnetic analysis on threepreviously unstudied Ryugu particles: A0397, C0085b, andC0006. These samples have not been previously studied using a
microprobe or instrument with a strong magnet prior to our
paleomagnetic analysis.
Alternating field (AF) demagnetization of the NRM in
A0397 to 400 mT in steps of 0.5-1 mT revealed two non-origin
trending components (Fig. 1), a low coercivity (LC) component
that unblocked between 0 and 10.5 mT and a medium coercivity(MCs) component that unblocked between 11 and 23.5 mT.
Above >24 mT is a high coercivity (HC) range in which no
Figure 2: Predicted midplane nebular field assuming accretion
NRM components are observed. AF demagnetization of C0085b
around a solar mass star and that the nebular field and disk rotation
to 400 mT revealed three NRM components: an LC component
are aligned. Accretion rates are given at the right-hand side foreach curve. Colored lines represent constraints on heliocentricthat unblocked between 0 and 12.5 mT, and two MC
distance at which aqueous alteration occurred based on uppercomponents that unblocked between 13 and 19 mT and 19.5 andpaleointensity limits from particles C0085b and A0397.
23.5 mT, respectively. The second MC component was origintrending. As before, above >24 mT is a HC range containing no stable NRM. AF demagnetization of C0006 to 80 mT conductedin 5-10 mT steps revealed a non-origin trending LC component that unblocked between 0 and 20 mT with no apparent
components in the HC range above 20 mT.
Paleointensities estimated via the anhysteretic remanent magnetization (100 µT bias field and 260 mT AC field) method
for the LC components are 125.8 ± 28.9 (95% confidence interval, as for all below), 694.6 ± 145.5 and 44.8 ± 69.5 µT for A0397,
C0085b, and C006 respectively. The MC paleointensity for A0397 is 45.6 ± 31.6 µT, while the two MC paleointensities for
C0085b are 36.0 ± 44.4 and 62.3 ± 134.7. Importantly, the HC paleointensities are all also consistent with null paleofields: 26.4
± 30.6 µT for C0085b, 7.4 ± 9.2 µT for A0397, and 8.8 ± 16.4 µT for C0006. This indicates that there are magnetic recorders
with coercivities >24 mT in the particles that are capable of recording an ancient field but instead formed in the presence of anull or weak field.
Experiments conducted to determine the susceptibility of A0397 to viscous (VRM) remagnetization from prolonged
exposure to an Earth-strength field indicate that the total moment gained over 4.5 years (initial sampling to NRM
demagnetization) could account for 98% of the combined LC and MC components. We therefore suggest that the source of the
LC and MC components in our samples are overprints, most likely a VRM from sitting in Earth’s field and the field producedby spacecraft engines (10s of µT [16]) since sampling. The non-origin trending nature of the two A0397 components further
indicate that they are not primary. We suggest that the previously reported strong paleointensities are due to a weak IRM fromthe electron microprobe as ratio of NRM to saturating IRM is >10% and the components are not origin trending as well.
Our results have profound implications for the history of the Ryugu parent body. Taking the alteration age to be < 1.8
Ma after CAI-formation, our most stringent upper paleointensity limit of 7.4 µT indicates that alteration occurred at heliocentric
distances >15 AU for typical accretion rates during the main lifetime of the nebula of 10-8 M☉ yr-1 (and >5 AU for the lower
range of accretion rates during the main lifetime of the nebula) (Fig. 2). Given Ryugu’s current location (~1 AU), the parent
body may have been scattered inward prior to catastrophic disruption, but after experiencing aqueous alteration, due to influence
from the giant planets in a similar manner to that proposed for the parent body of Tagish Lake. Our results therefore provide
further evidence that the formation and migration of the giant planets led to a major reconstructing of the organization of thesolar system.
References[1] B. P. Weiss, X. Bai, R. R. Fu. 2021. Science Advances. 7. [2] R. R. Fu et al. 2014. Science. 346. [3] C. S. Borlina et al.
2021. Science Advances. 7. [4] R. R. Fu et al. 2020. Journal of Geophysical Research: Planets. 125. [5] J. Gattacceca, B. P.
Weiss, M. Gounelle. 2016. Earth and Planetary Science Letters. 455. [6] B. P. Weiss et al. 2008. Science. 322. [7] B. P. Weisset al. 2017. Earth and Planetary Science Letters. 468. [8] J. F. J. Bryson et al. 2020. The Astrophysical Journal. 896. [9] J. F. J.
Bryson et al. 2020. The Astrophysical Journal. 892. [10] S. N. Raymond, A. Izidoro. 2017. Sci Adv. 3. [11] T. Hopp et al.
2022. Science Advances. 8. [12] Y. Kimura et al. 2023. Sci Rep. 13. [13] B. P. Weiss et al. 2010. Space Science Reviews. 152.
[14] T. Nakamura et al. 2023. Science. 379. [15] K. A. McCain et al. 2023. Nature Astronomy. 7. [16] M. Sato et al. 2022.
Journal of Geophysical Research: Planets. 127. [17] D. Hercik et al. 2020. Journal of Geophysical Research: Planets. 125.

Experimental Constraints on the Concentration of Dirac Magnetic Monopoles in Primordial
Material returned from Asteroid Ryugu by JAXA’s Hayabusa2 Mission
Joseph L. Kirschvink1,2, Michael Sowell1, Chisato Anai2, Atsuko Kobayashi1,2, Yuhji Yamamoto2, Elias Mansbach3, Eduardo
Lima3, Masahiko Sato4, Chie Kato5, Hirosi Ooguri1,6, Tadayuki Takahashi6, Thomas Edward Melia6, Alexander Kusenko6,7,Volodymyr Takhistov6,8, Tomohiro Usui9
1
California Institute of Technology, Pasadena CA, USA2
Kochi Marine Core Research Institute, Kochi University, Japan
3
Massachusetts Institute of Technology; Cambridge, MA, USA
4
University of Tokyo, Tokyo, Japan; 5Kyushu University, Fukuoka, Japan
6
Kavli Institute of Physics and Mathematics of the Universe, University of Tokyo, Tokyo, Japan
7
University of California at Los Angeles, Los Angeles, CA, USA
8High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
9
JAXA, Kanagawa, JapanIn 1931, Dirac postulated the existence of elementary particles with quantized magnetic charge as an explanation for theobserved quantization of electric charge. If found, Dirac magnetic monopoles (DMMs) would require a re-evaluation ofelectromagnetism and all related theories. However, DMMs have not yet been empirically discovered. Their predicted
magnetic charge, multiples of 2Φ0 (where Φ0 is the magnetic flux quantum: ~2.07 fWb), would be detected easily withmodern superconducting quantum interference device (SQUID) magnetometers. If cosmic DMMs were trapped on
ferromagnetic grains in pre-solar materials, then a promising place to search for them would be in material sampled fromprimitive small bodies, preferably returned by spacecraft on low-acceleration trajectories, since intense accelerations
experienced by meteorites could strip them of DMMs as they enter Earth’s atmosphere. By passing material through a 2G
SQUID rock magnetometer, a theoretical DMM trapped within ferromagnetic grains would return a change in measured
magnetic flux (ΔΦ) by multiples of 4Φ0, or ~8.23 fWb. We performed this experiment on three Hayabusa-2 samples returned
from the asteroid Ryugu: samples collected from the sites TD1 (A0397) and TD2 (C0006 and C0085), with a combined massof 18.7 mg. We measured ΔΦ as -0.3 ± 0.2 fWb for A0397, 0.3 ± 0.5 fWb for C0006, and 0.4 ± 1.1 fWb for C0085. Although
our numbers were not significantly different from zero and are well below the expected magnetic charge for DMMs, we only
sampled 18.7 mg of the ~5g of primitive asteroidal material returned from Ryugu, which is in turn an infinitesimal fraction of
the solar system. Due to their importance for all of science, we argue that all primitive materials returned from space missions
should be screened routinely for DMMs as part of their initial characterization in the sample receiving laboratories.

Summarized results of 22 pass-through experiments conducted on returned Ryugu samples A0397, C0006, and C0085. Here,ΔΦ is expressed as a percentage of 4Φ0 – the minimum quantized change in flux expected by a Dirac magnetic monopole.
Since ΔΦ of all samples is much lower than 4Φ0, we have not yet detected a magnetic monopole.

Electron holography observation of presudo-magnetites and metallic iron nanoparticles in space
weathered Ryugu sample
Yuki Kimura1, Takeharu Kato2, Satoshi Anada2, Ryuji Yoshida2, Kazuo Yamamoto2, Toshiaki Tanigaki3, Tetsuya Akashi3,
Hiroto Kasai3, Kosuke Kurosawa4, Tomoki Nakamura5, Takaaki Noguchi6, Masahiko Sato7, Toru Matsumoto6, Tomoyo
Morita5, Mizuha Kikuiri5, Kana Amano5, Eiichi Kagawa5, Toru Yada8, Masahiro Nishimura8, Aiko Nakato9, Akiko Miyazaki8,
Kasumi Yogata8, Masanao Abe8, Tatsuaki Okada8, Tomohiro Usui8, Makoto Yoshikawa8, Takanao Saiki8, Satoshi Tanaka8,
Fuyuto Terui10, Satoru Nakazawa8, Hisayoshi Yurimoto11, Ryuji Okazaki12, Hikaru Yabuta13, Hiroshi Naraoka12, Kanako
Sakamoto8, Sei-ichiro Watanabe14, Yuichi Tsuda8, and Shogo Tachibana6,81
Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
2
Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan.
3
Research & Development Group, Hitachi, Ltd., Hatoyama, Saitama, 350-0395, Japan.
4Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan.
5
Department of Earth Sciences, Tohoku University, Sendai 980-8578, Japan.
6
Division of Earth and Planetary Sciences, Kyoto University; Kyoto 606-8502, Japan.
7
Department of Earth and Planetary Science, The University of Tokyo, Tokyo 113-0033, Japan.
8Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan.
9
National Institute of Polar Research, Tashikawa 190-8518, Japan.
10
Kanagawa Institute of Technology, Atsugi 243-0292, Japan.
11
Department of Natural History Sciences, Hokkaido University, Sapporo 060-0810, Japan.
12Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 819-0395, Japan.
13
Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
14
Department of Earth and Environmental Sciences, Nagoya University, Nagoya 464-8601, Japan.
The traces resulting from space weathering could provide a detailed understanding of interplanetary processes. However,most meteorites are composed of materials produced in the interior of the asteroid and have not undergone space weathering
on its surface. Analysis of samples gently collected from the surface of extraterrestrial bodies by spacecraft is therefore
useful for studying the details of space weathering [1,2].
Here, we focused on the space weathering of magnetite in samples brought back from the C-type asteroid Ryugu by the
Hayabusa2 spacecraft. Magnetite is an important mineral to record the nebular magnetic field, but studies on its space
weathering are limited. Magnetite is universally found in carbonaceous meteorites as a major product of aqueous alterationof asteroids during the early stages of solar system formation. In particular, since most of the samples recovered by the
Hayabusa2 spacecraft were collected from the surface of the asteroid, it is important to understand the degree of space
weathering influence on magnetite in order to interpret the origin of remanent magnetization. We have previously studied themagnetic domain structure of framboidal magnetite in recovered samples using electron holography [3,4]. In this study, we
report on our newly discovered flamboids, which does not show a typical magnetic domain structure of magnetite.
From an area with relatively abundant Fe and containing many spherical particles similar to framboidal magnetite wasselected from the surface of particle A0064-FO007 and an ultrathin section was prepared by focused ion beam (FIB)
machining without applying magnetic field greater than that of the Earth. The ultrathin section contained about a dozen
framboidal magnetite particles with sizes ranging from 500-900 nm (Fig. 1A). The magnetic domain structures of theseparticles were observed by electron holography (HF-3300EH; Hitachi High-Tech Corp., Tokyo), and it was found that themagnetic domains of each particle had a concentric magnetic structure typical of submicrometer-sized magnetite particles (Fig.
1B) [5-8].
Ultrathin sections taken from neighboring locations of the same particles also contained flamboidal particles of 400-800
nm in diameter, similar to Fig. 1A (Fig. 1C). The scanning transmission electron microscopy–energy-dispersive X-ray
spectrometry analysis of this particle confirmed that it was iron oxide, consistent with magnetite, but electron holography
showed no magnetic domain structure. This suggests that the particle is a nonmagnetic mineral and not magnetite. We
analyzed the bonding state of iron and oxygen using electron energy loss spectroscopy and found that this nonmagnetic particle
exhibited characteristics of both magnetite and wüstite in terms of the bonding state of iron and oxygen. We named suchparticles that exhibit both features of magnetite and wüstite, and do not show a magnetic domain structure "pseudo-magnetite".
Around the pseudo-magnetite particles, there was a decrease in signal intensity of various light elements in the region of
about 2 μm below the surface. In addition, the elemental mapping of iron shows many small iron particles that may have

been released or diffused from the pseudo-magnetite (Fig. 1E). More than 100 metallic iron particles of 30-400 nm were
easily counted in an alteration region 2 µm deep, 10 µm long, and 0.1 µm thick from the surface. Assuming that thisreduction is due to a micrometeoroid impact and that a 10-μm diameter region is altered to a depth of 2 μm in a single impact,
the total number of iron particles produced would be ~104, which could acquire remanent magnetization during an event
involving the formation of iron nanoparticles by a micrometeoroid impact. Therefore, the iron particle precipitation
associated with a micrometeoroid impact could play an important role as the remanence acquisition event.
Micrometeoroid impacts are thought to have occurred frequently within protoplanetary disks. However, the traces left
behind by these impacts are found only on the topmost surfaces of asteroids, so previous studies using meteorites have had
limited opportunities to study these traces. Even if a meteorite fell to Earth leaving behind pseudo-magnetite and ironparticles, these particles would be oxidized by weathering on the ground afterward. In addition to the samples obtained by
the Hayabusa2 spacecraft, the samples brought back from the asteroid Bennu by OSIRIS-REx will also have a chance to beanalyzed. In this process, it is necessary to avoid changes in remanent magnetization due to oxidation of pseudo-magnetiteand metallic iron nanoparticles. Although pseudomagnetite may represent only a small percentage of total magnetite, itspresence should be considered when analyzing extraterrestrial samples recovered from an asteroid surface. In ourpresentation, the event and timing of the micrometeorite impact and other suspect magnetite particles will be discussed.

Figure 1. Framboids with and without magnetic domain structures characteristic to magnetite. A and B. Bright field
TEM and the corresponding magnetic-flux-distribution images, respectively, of framboidal magnetite particles in a thin section
prepared from the A0064–FO007 sample of asteroid Ryugu. C. Bright field TEM image of pseudo-magnetite particles in a thinsection prepared from neighboring region of A. D. Magnetic-flux-distribution image, corresponding to the box d in C,
observed by electron holography. E. Elemental mapping of iron corresponding to the box e in C.
The authors thank the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (grants
JPMXS0450200421, JPMXS0450200521) for financial support and JEOL for providing access to the tabletop SEM (JCM7000, NeoScope). We thank the developers of iSALE, including G. Collins, K. Wünnemann, B. Ivanov, J. Melosh, and D.
Elbeshausen. We also thank Tom Davison for the development of pySALEPlot.
References[1] Noguchi T. et al. 2011. Science 333:1121. [2] Noguchi T. et al. 2023. Nat. Astron. 7:170. [3] Nakamura T. et al. 2022.
Science 379: eabn8671. [4] Kimura Y. et al. 2023 Scientific Reports 13:14096. [5] Kimura Y. et al. 2013. Nat. Commun.
4:2649. [6] Almeida T. P. et al. 2014. Nat. Commun. 5:5154. [7] Almeida T. P. et al. Geophys. Res. Lett. 41:7041. [8]Kimura Y., Yamamoto K. & Wakita S. 2021. Astrophys. J. Lett. 917:L5.

Characterization Of Early Solar System Aqueous Fluids In Ryugu Samples
Michael Zolensky1, Robert Bodnar2, Andrei Dolocan3, JangMi Han4, Romy Hanna3, Iona Gearba3, Queenie Chan5,
Trevor Ireland6, Megumi Matsumoto7, Akira Tsuchiyama8.
1NASA JSC, Houston, TX 77058, USA (michael.e.zolensky@nasa.gov); 2Virginia Tech, Blacksburg VA 24060,
USA;3Univ. of Texas, Austin TX 78712, USA; 4University of Houston, Houston TX 77204, USA; 5Royal Holloway
University, Egham Hill, Egham TW20 0EX, UK; 6University of Queensland, St Lucia 4072, Queensland, Australia;
7
Tohoku University, Aoba-ku, Sendai, Miyagi, Japan; 8Ritsumeikan Univ., Kusatsu, Shiga, 525-8577, Japan
Introduction: The most direct and convincing evidence for the presence of water and organic molecules on
protoplanetary bodies is provided by fluid inclusions trapped in secondary minerals. Our previous research has
demonstrated that early solar system fluids have survived as fluid inclusions in a few astromaterials that escaped
significant shock, terrestrial alteration, and invasive sample handling [1-3]. We hypothesize that the bulk molecularand isotopic composition of individual fluid inclusions can be measured to provide ground truth for exploring andthermochemical modeling of the compositional and isotopic evolution of fluids in protoplanetary bodies including
asteroids, comets and icy moons.
This presentation is an update on our efforts to make measurements of elemental, molecular and isotopic
compositions of individual aqueous fluid inclusions in Ryugu samples.
Facilities: For the following XRCT and TOF-SIMS analysis, samples were prepared using the FEI Quanta 3D 600
Dual-beam Focused Ion Beam in the ARES -NASA-JSC Electron Beam Instrument Facility. For the X-ray Computed
Tomography (XRCT) scans we used the Zeiss 620 XRM instrument at the University of Texas High-Resolution Xray Computed Tomography Facility. For the Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS)
measurements we used the University of Texas Materials Institute’s TOF-SIMS 5 and TOF-SIMS 6 instruments (IONTOF GmbH) equipped with a pulsed Bi+ analysis ion beam (30 keV ion energy) and a O2+ sputtering ion beam (1 kV
ion energy). The TOF-SIMS instruments are capable of cooling the samples to -160 and -180C, respectively, andwithout this capability our measurements would be impossible.
Aqueous Fluids: Studies of aqueous alteration in primitive meteorites, based solely on secondary mineral
associations, have hinted that this process did not occur under a single set of conditions [4]. The temperatures ofalteration that have been suggested are highly variable, from below 0 to ~250°C. The fluid compositions must have
likewise varied, though this critical aspect is very poorly understood. Our previous molecular, O and H isotopic
measurements of fluids in halite in the Monahans and Zag meteorites [2,5] have shown considerable variation in fluid
composition even within individual crystals. For example, we suspect that early solar system aqueous fluids could
alternate between being S-rich and S-poor, based on the alternating pyrrhotite-magnetite alteration assemblage
observed in the Tagish Lake and Sutter’s Mill chondrites [6]. We know from our previous studies of aqueous fluidinclusions in extraterrestrial halite and calcite in the Sutter’s Mill C2 chondrite that the mineralizing fluids also
contained a significant concentration of mineralizing cations such as Fe, Mg, Ca, and volatiles such as CO 2 and Sbearing compounds in variable abundances (though the abundances are not yet determined) [2,7]. We observed CN-,a molecular fragment of a larger nitrogenous compound, in the aqueous fluid inclusions in a Ryugu pyrrhotite crystal[1-3]. Nakamura et al. [3] reported that the earliest formed phyllosilicates in Ryugu were rich in Na, indicating
significant compositional changes in the mineralizing fluid.
Ryugu Fluid Inclusion Measurements: Our recent successful, coordinated, XRCT and TOF-SIMS analyses ofindividual fluid inclusions in a Ryugu pyrrhotite crystal demonstrated that they consist of water, CO2, sulfur species,
and organic material, with H-, C-, O-, S- and OH- as the main fragments detected at these locations [1,3]. In addition,
various amounts of F-, Cl- and Ni- were found, together with Na+, Mg+, Al+, Cr+, K+ and Ca+. Larger organic fragments
such as C2-, C2H-, C3-, CO- and CN- were also detected, indicating the presence in these inclusions of more complex
organic molecules containing H, C, N and O. We can expect to see these and additional molecular fragments in other
Ryugu fluid inclusions. TOF-SIMS breaks apart molecules - it does not make new ones. Therefore, all these identified
species are fragments of once larger molecules which we can identify to some degree.
Measurement of the stable isotopic compositions of aqueous fluid inclusions in Ryugu samples will enable a
comparison with our measurements of a few fluid inclusions in carbonaceous chondrites (e.g. [7]), and fluids
calculated to have reacted with other primitive samples (CI chondrites, OCs, HEDs, ureilites) which have δD ranging
from ~0-3000‰. Actual direct measurements of preserved trapped fluids would thus inform us about fluid changes
during aqueous alteration in a large suite of primitive bodies. Russell et al. [8] has suggested that CI materials form

two groups with distinct water/rock ratios, temperature ranges, and hydrogen isotope compositions. Are these truly
distinct groups or do these just represent endmembers of a poorly sampled complete range (as also suggested byRussell et al., [8])? Our planned analyses of individual fluid inclusion oxygen and hydrogen isotope compositions in
Ryugu samples will settle this issue as we will either observe narrow compositions or a compositional continuum.
Polished Ryugu sample C00025 contains large sulfides, magnesite, magnetite and dolomite crystals (Fig 1). We
have already FIBed several foils from this sample and subjected one of the FIB foils to TOF-SIMS measurements.
We detected no filled fluid inclusions, however we were limited to analyzing inclusions larger than about 3 μm using
the M5 TOF-SIMS instrument, and it appears the inclusions were far smaller (Fig.1). We plan to repeat themeasurements of this sample using the newly-installed M6 TOF-SIMS, which has greatly expanded capabilities. We
made XRCT scans of two additional Ryugu grains (A0175 and C0043) (Fig 2). From these preliminary measurements
we know that A0175 contains numerous pyrrhotite, carbonate, and, probably, apatite crystals with fluid inclusion
candidates measuring at least 3-5 µm in diameter, which will permit our planned TOF-SIMS measurements.
The TOF-SIMS analytical data are counts under the peaks for each species. An example of the data is shown in
Figure 3, which shows counts for OH- (indicative of H2O) and C- (here indicative of CO2). This sample was a synthetic
fluid inclusion standard (quartz) prepared by Bob Bodnar where the inclusions contained a 1:1 mixture of H 2O and
CO2. As you can see from the included table, despite the fact that the sensitivity of the technique for CO 2 was much
lower than for H2O, 4/5 of the inclusions showed consistent counts for these species, meaning that with continued
calibration we can produce quantitative composition measurements for some species. We note that the signals for CO2
we observed in the Ryugu pyrrhotite crystal were more pronounced than those we obtained using the 50:50 standard,suggesting a very high abundance of CO2 in the Ryugu mineralizing fluid. In fact, solid CO2 sublimed rapidly in a
vacuum at our measurement temperature, making quantification very difficult.
In the coming year we will begin isotopic measurements of standards in synthetic fluid inclusions and Ryugu
pyrrhotites and carbonates we have already identified, as well as increasing our stock of pre-analyzed Ryugu crystals.
Fig. 1. Magnesite in Ryugu sample C00025 (left) BSE image ofMagnesite showing FIB pits. (right) SEI image FIB A foil
showing submicron-sized fluid inclusion candidates circled.
Acknowledgements: We thank JAXA for Ryugu samples, andthe NASA Hayabusa2 Participating Scientist Program.
References: [1] Zolensky et al. (2022) 85th Meeting of The
Meteoritical Society. Abstract 6011; [2] Bodnar et al. (2019) 50th
LPSC Abstracts; [3] Nakamura et al. (2022) Science 377,
10.1126/science.abn8671; [4] Brearley (2005) In Meteorites andthe Early Solar System II. D. S. Lauretta and H. Y. McSween Jr.,
Eds.; [5] Yurimoto et al. (2014) Geochemical Journal 48, 1-12;[6] Zolensky et al. (2014) MAPS 49, 1997-2016; [7] Tsuchiyama
et al. (2021) Science Advances 7, eabg9707; [8] Russell et al.
(2022) MAPS 57, 277–301.
(Left) Fig. 2. XRCT “slices” of
Ryugu sample A0175. Fluid
inclusion candidates are arrowed.
(a-e) Pyrrhotite crystals. (f-g)
Probable carbonates. (h) Possible
apatite crystal.
(Right) Fig. 3. Results of TOFSIMS measurements of synthetic
fluid inclusion standard (quartz),with inclusions that contain a 1:1
mixture of H2O and CO2. Inclusions are numbered to match thetable (e.g. ROl1=1). Counts = cts.

Three-dimensional description and characterization of lithologies in Ryugu sampleLéna Jossé1 , Zélia Dionnet1 , Alice Aléon-Toppani1 , Rosario Brunetto1 , Andrew King2 , Emmanuel Gardés3 , Eva Heripré4 ,Donia Baklouti1 , Zahia Djouadi1 , Cateline Lantz1 and Kentaro Hatakeda5
1
CNRS, Institut d’Astrophysique Spatiale, Université Paris-Saclay, Orsay, France
2
SOLEIL Synchrotron, Gif-sur-Yvette, France
3
Laboratoire Magmas et Volcans, Clermont-Ferrand, France
4
Procédés et Ingénierie en Mécanique et Matériaux, Paris, France
5
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA), Japan

Ryugu is a rubble-pile asteroid. Similarly to CI chondrites, the samples returned by Hayabusa2 mission showed the presenceof adjoining fragments of different lithologies [1, 2]. These fragments are different in mineralogy, petrology, physical structure(size, porosity) and testify the heterogeneity of Ryugu’s asteroid, its complex geological history and evolution [3]. So far, several
lithologies have been observed and described partly in polished sections [1, 2, 3]. In this work we used micro-computed tomography (µ-XCT) to observe, analyze and investigate lithologies in 3D. We analyzed their properties (internal structure, shape, size,
composition, porosity) and their assemblages with each other in a Ryugu millimeter-sized sample with the objective to better
understand Ryugu’s heterogeneity and its complexity in term of formation and evolution.
We studied the 3D lithologies of the mm-sized (1.45×2.85×2.1 mm) sample A0159 from Chamber A. Data were obtainedat PSYCHÉ beam-line of Synchrotron SOLEIL (France) using a monochromatic X-ray beam operating at 25 keV. Our analysis
was conducted on 3D reconstructed images (CT-images, or “slices”) with a voxel volume of 1.295 µm3 and based on the linear
attenuation coefficient (LAC). As a first method of data processing, we used pixel segmentation, which classifies each voxel
into 5 major domains by its LAC value. The domains are, sorted by increasing LAC, 1-porosity, voids, fractures, 2-matrix,
3-carbonates, 4-sulfides and oxides. Some LAC values were difficult to associate with a specific domain so we classified themas 5-uncharacterized. This method allows us to obtain the proportion of each component within each slice and then in the entire
sampl5, but also the 3D reconstruction of each component.
Contrary to the first method, the local histogram segmentation considers areas of 49×49 voxels. For each area, the calculated
histogram of the proportion of pixels for a given LAC value gives access to i) the number of pixels for each of the 5 previously
cited domain and ii) the LAC histogram data distribution. Then, each area was locally described in regard to composition andphysical properties giving rise to lithologies. This method allowed us to obtain a 3D reconstruction of each lithology in thesample. Tomviz software was used for 3D representation and visualization.
Our preliminary results from the pixel segmentation
method showed that, on average, A0159 is made of 42.0±7.0 %of matrix component, 1.2±0.5 % of sulfides and oxides,
4.7±2.8 % of porosity, voids and/or fractures and 27.5±4.7 %of uncharacterized material (undefined components, or technique artifacts). Finally, carbonate components represents
24.1±2.5 % of the sample, a much higher value than previous studies [4]. The 3D reconstruction of carbonates shows
a mm-sized vein going through A0159 (fig. 1), indicating important fluid circulation. The vein is about 1100×900×100 µm
and it is the largest vein observed so far in a Ryugu sample.
Its presence explains the high proportion of carbonate materialin A0159. We detected two highly fractured plans along bothsides of the vein. The vein ends up with coarse and elongatedto rounded carbonate grains with inter-grains voids. In otherstudies, a complex and elongated structure of size >100 µm
was observed in sample C0041 and found to have a wide rangeof (Mg-Fe)-carbonate composition between siderite–magnesite(or breunnerite) [5, 6]. In sample C0009, [3] found elongatedCa-carbonates forming a chain that they proposed to be a potential remnant of a vein. The detection of a mm-sized vein in

A0159 suggests that Ryugu’s parent-body has probably undergone notable water flow through, at least, a mm-sized fracture
and that carbonate precipitated as a vein.

Figure 1: 3D reconstruction of the Ryugu sample A0159 (in grey)
combined with the distribution of carbonates (in yellow).

The preliminary results of the second method allowed us to detect several different lithologies. A study is ongoing todetermine the exact number of lithologies. These lithologies are mostly composed of matrix with various size and proportionof carbonates, sulfides, oxides, and porosity. One peculiar lithology is made of a compact matrix component, few carbonates,
uncharacterized material, sulfides and oxides. This lithology could match the ”massive domain” seen by [1] in A0035 or the”fine-grained dark lithology” in C0009 by [3]. The compact lithology is surrounded by long (up to 800 µm) and large fractures(up to 20 µm) and, similarly to [1], some fractures also cross the lithology. Another lithology is rich in rounded and elongatedgrains of carbonates about 50 µm in size and is located at the end of the vein. This lithology has many small fractures (up to
100 µm long and 10 µm large) which seem to be preferably located around the grains such as in A0037 [3]. However, crossing
and surrounding fractures are not present in each lithology. The second method is still ongoing and it is not clear yet whether
the carbonate vein crosses a single lithology. However, our preliminary results confirm that Ryugu is a breccia with adjoining
fragments of various size (from 100 to 500 µm), composition and physical properties. The analysis of the fractures (distribution,
size and shape) strongly indicates a heterogeneity in the mechanical properties of lithologies. All these observations testify thecomplexity of Ryugu and/or parent-body formation and evolution and its geological past.

References[1] E. Nakamura, K. Kobayashi, R. Tanaka, T. Kunihiro, H. Kitagawa, C. Potiszil, T. Ota, C. Sakaguchi, M. Yamanaka, D. M.
Ratnayake, et al., “On the origin and evolution of the asteroid ryugu: A comprehensive geochemical perspective,” Proceedings of the Japan Academy, Series B, vol. 98, no. 6, pp. 227–282, 2022.
[2] T. Nakamura, M. Matsumoto, K. Amano, Y. Enokido, M. Zolensky, T. Mikouchi, H. Genda, S. Tanaka, M. Zolotov,
K. Kurosawa, et al., “Formation and evolution of carbonaceous asteroid ryugu: Direct evidence from returned samples,”Science, p. eabn8671, 2022.
[3] A. Yamaguchi, N. Tomioka, M. Ito, N. Shirai, M. Kimura, R. C. Greenwood, M.-C. Liu, K. A. McCain, N. Matsuda,
M. Uesugi, et al., “Insight into multi-step geological evolution of c-type asteroids from ryugu particles,” Nature Astronomy, vol. 7, no. 4, pp. 398–405, 2023.
[4] C. Pilorget, T. Okada, V. Hamm, R. Brunetto, T. Yada, D. Loizeau, L. Riu, T. Usui, A. Moussi-Soffys, K. Hatakeda, et al.,“First compositional analysis of ryugu samples by the micromega hyperspectral microscope,” Nature Astronomy, vol. 6,
no. 2, pp. 221–225, 2022.
[5] D. Loizeau, C. Pilorget, L. Riu, R. Brunetto, J.-P. Bibring, A. Nakato, A. Aléon-Toppani, K. Hatakeda, K. Yogata, J. Carter,
et al., “Constraints on solar system early evolution by micromega analysis of ryugu carbonates,” Nature Astronomy, pp. 1–
7, 2023.
[6] A. Nakato, T. Yada, M. Nishimura, K. Yogata, A. Miyazaki, K. Nagashima, K. Hatakeda, K. Kumagai, Y. Hitomi, H. Soejima, et al., “Variations of the surface characteristics of ryugu returned samples,” Earth, Planets and Space, vol. 75, no. 1,
p. 45, 2023.

Size distribution and elemental compositions of anhydrous minerals in the Ryugu samples C0224 andC0260: Implications for radial transport mechanism and source regions of anhydrous minerals
D. Nakashima1, M. Matsumoto1, H. Yoshida2, T. Mikouchi2, T. Nakamura1
1
Tohoku University, Japan (dnaka@tohoku.ac.jp), 2University of Tokyo, Japan.
Introduction: Samples returned from C-type asteroid Ryugu by the Hayabusa2 spacecraft are mineralogically and chemicallysimilar to CI chondrites [1-4]. It was suggested from the initial analysis of the Ryugu samples that the Ryugu original parent bodyformed beyond the H2O and CO2 snow lines (> 3 – 4 au) in the solar nebula at 1.8 – 2.9 Myr after CAI formation [1]. Nakashima etal. [5] reported elemental compositions and oxygen isotope ratios of chondrule-like objects and Ca-Al-rich inclusions (CAIs) in the
Ryugu samples. The objects (< 30 µm) are as small as those from comet Wild2, suggesting radial transport favoring smaller objects
from the inner solar nebula (solar neighborhood and chondrule formation regions) to the formation location of the Ryugu original
parent body, which is farther from the Sun and scarce in chondrules [5]. Besides chondrule-like objects and CAIs, anhydrous minerals such as olivine, pyroxene, spinel, and hibonite occur in the Ryugu samples and are much more abundant [1]. In the present
study, we measured size distribution of anhydrous minerals in the newly allocated Ryugu samples (C0224 and C0260) using FESEM and FE-EPMA to test the hypothesis of radial transport favoring smaller objects [5] and elemental compositions to elucidate
the source regions of individual anhydrous minerals.
Results: Synchrotron radiation X-ray computed tomography at SPring-8 showed that C0224 has a homogeneous lithology except for the presence of large carbonate crystals of few hundred µm in size and C0260 contains clasts with different lithologies.
Three hundred ten anhydrous minerals including chondrule-like objects were found in eight polished sections from C0260 (C026001, 02, and 03) and C0224 (C0224-01, 02, 03, 04, and 05), and most of them were from C0260. Polished sections of C0224 wererepolished multiple times but only 6 grains were observed. Most anhydrous minerals occur along with calcite, Ca phosphate, andNa-Mg phosphate in FeO-rich phyllosilicate regions, which is characteristic for lithology II clasts (less-altered clasts; [6]). Anhydrous minerals have angular shapes, so that diameters are calculated from surface areas of anhydrous minerals using ImageJ assuming they have spherical shapes. The largest one is 24 µm and smallest one is 0.5 µm. As shown in Fig. 1a, the peak of size distribution of anhydrous minerals including chondrule-like objects occurs at 2 – 3 µm. It should be noted that we counted anhydrous
minerals detected by FE-SEM mapping, and therefore there is counting loss of tiny minerals (<< 1 µm). Olivine is most abundantfollowed by spinel, pyroxene, and hibonite. Mg#’s of olivine are from 89.5 to 99.4, which is consistent with the initial analysis [1].
Low-iron manganese-enriched (LIME) olivine with MnO/FeO ratio (wt%) exceeding 1 [7] is observed. Pyroxene and hibonite
grains are too small to obtain precise compositions. Spinel contains variable amounts of Cr2O3 (0.21 – 4.0 wt%).
Six chondrule-like objects are observed (Fig. 1b). They have rounded shapes and mainly consist of FeO-poor olivine with Mg#from 92.0 to 99.2 along with diopside, rounded (oxidized) Fe-Ni metal, and altered phase. The chondrule-like objects are similar to
those found in the initial analysis [1,5].
Discussion: Most anhydrous minerals occur in less-altered clasts in the Ryugu samples [1, this study]. The clasts have protected anhydrous minerals from aqueous alteration and brecciation for ~ 4.6 Gyr, so that sizes of the anhydrous minerals reflect thoseduring accretion onto the Ryugu original parent body. Our new data (Fig. 1a) show that anhydrous minerals in the Ryugu samples(< 24 µm) are smaller than chondrules in chondrites (~ 500 µm; [8]) and isolated olivine in chondrites (> 20 µm; [9]), suggestingradial transport favoring smaller objects to the formation location of the Ryugu original parent body. There are two possible mechanisms for radial transport: a combination of advection and turbulent diffusion [10] and photophoresis [11]. Both mechanisms cantransport grains smaller than 30 µm. While the Ryugu original parent body formed at ~ 2 Myr after the CAI formation [1], photophoresis transports 10 µm grains beyond 10 au later than ~ 5 Myr after the CAI formation [11]. Considering the time window, acombination of advection and turbulent diffusion that transports ≤ 20 µm grains beyond 25 au within 1 Myr [10] would be more
likely for Ryugu. It will be more plausible by size distributions of anhydrous minerals in other Ryugu samples and CI chondrites.
Olivine in type I chondrules is more enriched in Cr2O3 and CaO than olivine in amoeboid olivine aggregates (AOAs) (Fig. 2a)[5]. 16O-rich chondrule-like objects, CAIs, and 16O-rich olivine in the Ryugu samples are distributed in the AOA area, while 16Opoor chondrule-like object and 16O-poor olivine are distributed in the type I chondrule area. The difference in the elemental compositions of olivine with different origins is explained by AOA olivine condensation from a residual gas depleted in the refractoryelements followed by isolation from the gas before condensation of Cr [5]. Olivine depleted in Cr2O3 and CaO may have formed

near the Sun, and olivine relatively enriched in the two elements may have formed in the chondrule formation regions. Thus, it ispossible to deduce the source regions of isolated olivine and chondrule-like objects based on the Cr2O3 and CaO concentrations.
Many of isolated olivine grains and olivine in chondrule-like objects in C0260 and C0224 distribute in the AOA area (Fig. 2b),which is consistent with the FE-EPMA analysis of olivine in CI chondrites [12]. The AOA-like olivine may have formed near theSun. It is considered from the high abundance of AOA-like olivine in the Ryugu samples and frequent occurrence of 16O-rich olivine in Wild2 particles [13] that olivine formed near the Sun were transported to the outer regions of the early solar nebula andsurvived due to lack of chondrule forming event that erases 16O-rich signature and original elemental compositions. On the contrary, isolated olivine in chondrites distributes in the type I chondrule area (Fig. 2c), and 16O-rich olivine is rare in chondrites [14]. It
is considered that 16O-rich olivine passed the chondrule formation regions and/or melted during chondrule forming events.
Nakashima et al. [5] reported that spinel in the Ryugu CAIs contain small amounts of Cr 2O3 with < 0.2 wt% and suggested that
the CAIs escaped from remelting event and may be as old as the oldest CAIs. Isolated spinel in C0260 show variable Cr 2O3 concentrations up to 4.0 wt%. Therefore, spinel that acquired Cr by remelting events are also present in the Ryugu samples. Considering the time window of accretion (within ~ 2 Myr after CAI formation; [1]), remelting events may have occurred during that period.
References: [1] Nakamura T. et al. (2022) Science 10.1126/science.abn8671. [2] Ito M. et al. (2022) Nat. Astron.
10.1038/s41550-022-01745-5. [3] Nakamura E. et al. (2022) Proc. Jpn. Acad. Ser. B 98:227. [4] Yokoyama T. et al. (2022) Science 10.1126/science.abn7850. [5] Nakashima D. et al. (2023) Nat. Commun. 14:532. [6] Mikouchi T. et al. (2022) LPSC LIII,#1935. [7] Klöck W. et al. (1989) Nature 339:126. [8] Friedrich J. M. et al. (2015) Chem. Erde 75:419. [9] Jacquet E. et al. (2021)
M&PS 56:13. [10] Hughes A.L.H. & Armitage P.J. (2010) ApJ 719:1633. [11] Moudens A. et al. (2011) A&A 531:A106. [12]Mikouchi T. et al. (2023) 86th Annual Meeting of The Meteoritical Society, #6178. [13] Nakashima D. et al. (2012) EPSL 357358:355. [14] Tenner T.J. et al. (2018) in Chondrules: Records of Protoplanetary Disk Processes 196. [15] Kurat G. et al. (1989)
Meteoritics 24:35. [16] Jones R. H. et al. (2000) M&PS 35:849. [17] Ushikubo T. et al. (2012) GCA 90:242. [18] Yamanobe M. etal. (2018) Polar Sci. 15:29. [19] Chaumard N. et al. (2021) GCA 299:199. [20] Jacquet E. et al. (2021) M&PS 56:13. [21] Ushikubo T. & Kimura M. (2021) GCA 293:328. [22] Weisberg M. K. et al. (2021) GCA 300:279.
1.2

80

0.6

● C0002-P5-C1-Chd
1■ C0002-P5-C2-Chd▲ C0040-02-Chd〇 Type I chondrules
0.8〇 AOAs◎ 16O-rich chondrule (a006)● 16O-rich olivine (Lit.)○ 16O-poor olivine (Lit.) 0.6

0.4

0.4

0.2

0.2

1

(a)

(b) C0260-02-Chd2
0.8

Ol

Cr2O3 (wt%)

Number

60

40

1.2

(a) Fig. 4 in [5]1.200 (c)0.2
0.4olivine
0.6in chondrites
0.81
Isolated(b) Isolated olivine & olivine inchondrule-like objects in C0224 &C0260
Isolated olivine■ C0260-01-Chd1◆ C0260-01-Chd2▲ C0260-02-Chd1▼ C0260-02-Chd2
C0260-03-Chd1
C0260-03-Chd2

0
1.2
0

0.2

0.4

0.6

0.8

1

1.2

1
0.8
0.6

Diop

20

1um

0.4
0.2

0
0

0
0

5

10

15

20

25

30

Diameter (µm)
Fig. 1: Size distribution of anhydrous minerals including chondrulelike objects in C0224 and C0260 (a) and backscattered electron imageof the chondrule-like object C0260-02-Chd2 (b). Ol, olivine; Diop,
diopside.

0.2

0.4

0.6

0.8

1

1.2

CaO (wt%)
Fig. 2: Comparison of concentrations between Cr2O3 and CaO inolivine in chondrule-like objects, type I chondrules, AOAs, 16O-richand -poor chondrules (a), isolated olivine and olivine in chondrulelike objects in C0224 and C0260 (b), and isolated olivine in chondrites (c). The panel a is from Nakashima et al. [5]. Olivine data inthe panel c are from [15-22].

Microstructural and microchemical characteristics of dolomite in Ryugu regolith particles
Falko Langenhorst1,2, Kilian Pollok1, Tomoki Nakamura3, Tomoyo Morita3, Kana Amano3, Daisuke Nakashima3
and the Hayabusa2 initial analysis core team1
Institute of Geoscience, Friedrich Schiller University Jena, Germany
2
Hawai’i Institute of Geophysics and Planetology, University of Hawai’i at Manoa, USA
3
Tohoku University, Sendai, Japan.
Introduction. Previous studies of Ryugu material have reported that the regolith particles record extensive aqueous alteration
as the result of water activity in the original parent body [1,2]. The aqueous alteration finally resulted in the almost complete
overprint of the primary mineralogical composition and the precipitation of secondary minerals, i.e. phyllosilicates, carbonates,
phosphates, sulfides, and oxides. The isotopic 18O/16O and 13C/12C signatures of carbonates were recently studied in great detailto obtain information on the conditions of aqueous alteration [3]. Here, we focus on the characterization of the defectmicrostructures and nanoscale element distributions in dolomite of Ryugu samples to obtain further insights into the formation
history and mechanisms of carbonates.
Samples and methods. In the context of the Hayabusa2 initial analysis phase, we have mainly studied polished sections
prepared from larger particles recovered in the C chamber, i.e. C0033-01 and C0033-04, and C0055-01 [detailed in 1]. Elevenslices of carbonate-bearing regions were cut from the thin sections by focused ion beam (FIB) preparation on a scanningelectron microscope (SEM). Subsequent analytical transmission electron microscopy (TEM) were performed according to theprocedure described by [4].
Results and discussion. TEM observations reveal numerous curled dislocations as the most dominant lattice defect in almost
all dolomite grains. This shape of dislocation lines indicate that dislocations are not in glide configuration and thus may havebeen incorporated during imperfect growth from the aqueous fluid. In the vicinity of fractures, sample C0055-01 contains alsostraight glissile dislocations, which were previously assigned to mild shock [5]. Deformation twins, which are generally
regarded as typical for shock-metamorphosed carbonates, are however absent in C0055-01. An explanation for their absence
could be that deformation twinning in dolomite requires enhanced temperatures [6], which do not prevail during low shock
metamorphism [6].
Mapping of elemental distributions in scanning mode using energy-dispersive X-ray emission spectroscopy show complex andvariable zoning of dolomite grains. Many grains show sharp, non-concentric, up to 1 µm thin rims with a significant
enrichment in manganese (up to 8 wt% MnO). This observation points, at least, to a second precipitation event, when the fluid
became apparently enriched in manganese. A preferential mobilization of manganese might be explained by a (localized)change in the reduction potential. In addition, manganese-enriched dolomites with continuously decreasing manganeseconcentration from core to rim exist and monitor a gradual change in the fluid chemistry controlled by carbonate growth.
Most interesting is the observation of nanoscale modulations in the rims of dolomite. Such microstructures have also been
observed in sedimentary calcian dolomites and are interpreted as growth microstructures [7]. The modulations appear as
almost parallel lamellae with regular alternating light and dark contrast, resembling microstructures known for spinodal
decomposition. A periodical variation of the fluid composition at the mineral-solution interface during progressing growth is a
plausible explanation for this microchemical peculiarity [8].
Acknowledgements. We thank JAXA for providing access to the Ryugu particles. FIB-TEM facilities at FSU Jena were
funded by the Gottfried-Wilhelm-Leibniz award to FL (LA 830/14-1).
References[1] Nakamura T. et al. 2023 Science 379:eabn8671. [2] Nakamura E. et al. 2022 Proc. Jpn. Acad. Ser. B:227-282. [3] Fujiya W.
et al. 2023 Nature Geoscience 16:675-682. [4] Langenhorst F., et al. 2014 Earth Planets and Space 66:118. [5] Kikuiri M. et al.
2022 85th Annual Meeting of The Meteoritical Society:No. 2695. [6] Barber D.J. and Wenk H.R. 1979 Physics Chemistry
Minerals 5:141-165. [7] Reeder R.J. 1992 In: P. Buseck (editor), Reviews in Mineralogy 27:381-424. [8] Ruiz-Agudo E. andPutnis C.V. 2012 Mineralogical Magazine 76:227-253.

Investigating the ammonium-bearing phase in Ryugu samples
M. Ferrari1, L. Folco2, S. De Angelis1, M. Masotta2, A. Raponi1, M.C. De Sanctis1, E. Mugnaioli2,
R. Borriello2, M. Ciarniello1, E. Ammannito3, E. La Francesca1, L. Rossi1, M. Pedone3.
1
INAF-IAPS, Via del Fosso del Cavaliere 100, 00133, Rome, Italy (marco.ferrari@inaf.it); 2Dep. Earth Science, University of
Pisa, Via Santa Maria, 53, 56126, Pisa, Italy; 3ASI, Via del Politecnico, 00133, Rome, Italy.
Introduction
The JAXA/Hayabusa2 mission collected 5.4 g of samples from two different sites (i.e., A and C) on the surface of the C-type
asteroid (162173) Ryugu [1; 2]. This asteroid is characterized by a low albedo and by the presence of hydrous andcarbonaceous materials [3]. The Ryugu surface spectra collected by the Hayabusa2/NIRS 3 spectrometer reveal a narrowabsorption feature at 2.72 μm [4] resembling that observed on the surface of Ceres by the Dawn/VIR spectrometer [5; 6].
Laboratory analysis of returned grains confirmed that Ryugu samples contain hydrated silicates, sulfides, oxides, carbonates,and organics and have spectroscopic similarities to CI chondrites [7]. MicrOmega hyperspectral microscope observation [8]revealed the presence of a band at 3.06 μm, indicating the possible presence of NH-bearing phases in most of the returned
grains [9]. This ammonium-related absorption feature was confirmed by FTIR measurements [10]. The 3.06 μm band was also
observed in the spectra of Ceres by telescopic observations [11] and by the Dawn/VIR spectrometer that accurately
characterized its distribution on the dwarf planet's surface [12]. Current interpretations of Ceres spectra suggest that the most
likely mineralogical phases hosting ammonium are phyllosilicates [13; 14], but the presence of ammonium salts has also beeninferred in specific areas of the Cerean surface [15; 16]. Hydrated silicates represent the main reservoir of water in Ryugu
samples, and their presence is indicative of extensive aqueous alteration in the parent body, likely the alteration path that
occurred on Ceres. Even if phyllosilicates are the most likely carriers, the specific ammonium-bearing phase determining the3.06 μm band on Ryugu samples and the surface of Ceres is not fully constrained, nor are the processes that led to ammonium
enrichment on these C-type bodies.
Sample selection
Our selection criterion of the samples among those available in the first allocation (2022A) was the presence of the absorption
band at 3.06 µm as observed in the spectroscopic data obtained from the preliminary screening by FTIR and MicrOmega. We
have considered: 1. Similarities of the 3.06 µm absorption between Ryugu samples and Ceres spectra, in terms of wavelength
range and band center position; 2. The presence of surface features or morphological structures suggests some mineralogicaldiversity.
Through the first allocation, we obtained two samples: A0198 and C0091. The preliminary FTIR data provided by JAXA
collected on particle C0091 show the presence of a remarkable absorption close to 3.06 μm. On the contrary, the spectroscopic
data collected on particle A0198 show a shallow absorption ascribed to the presence of ammonium and several surface featuresthat comply with our scientific requirements. Moreover, the two assigned samples were collected at different sites which willallow us to make further considerations.
Objectives and research plan
With this work, we aim to contribute to the definition of the physical and mineralogical characteristics of the Ryugu asteroid tounderstand the initial stages of formation and evolution of C-type bodies; particular attention will be given to the identificationof the ammonium-bearing phase(s) and its/their interplay with hydrated silicates. In addition, we aim to define Ryugu's path ofalteration and its similarities with Ceres.
The following laboratory analyses will be used to characterize the samples:•VIS-IR imaging spectroscopy (0.4-5 μm) will be carried out with the SPectral IMager (SPIM) facility [17] on whole samples.
Data will allow a first characterization of the mineralogic composition of their external surface, including an assessment of thepresence of water, organic matter, and ammonium in addition to the minerals. Furthermore, by using the SPIM facility (i.e., theDawn/VIR replica), we can perform a compelling comparison between the data collected on the samples with those provided
by the Dawn/VIR spectrometer on Ceres;•X-ray microscopy (XRM). This non-destructive technique has been used to obtain a high-resolution (submicron scale) 3D
tomography of the samples, revealing their internal structure (including pore structure and fracturing), as well as themorphology and composition of the individual grains contained in them; XRM data will also enable the location of regions ofinterest (ROIs) within the samples to be analyzed by transmission electron microscopy (TEM);

•Raman µ-spectroscopy, to obtain compositional maps of the surface of the samples at the micro-metric scale;•Focused ion beam-field emission gun-scanning electron microscopy (FIB-FEG-SEM) will be used to identify the mainmineralogical phases and to extract the electron-transparent lamellae for TEM analyses;•Transmission Electron Microscopy (TEM), electron diffraction, and energy-dispersive X-ray spectroscopy (EDS) will be used
to identify cryptocrystalline mineral phases and crystal defects through high-resolution techniques.
Results
The VIS-NIR spectra obtained with the SPIM facility on the surface of the two particles show the almost ubiquitous presenceof a deep V-band centered at lengths slightly above 2.7 μm, and absorptions near 3.4 μm and in the range 3.7-3.9 μm, however,limited at specific points on the surface returning an inhomogeneous surface composition at the scale of ~40 µm (SPIM pixelsize). These absorption features can be related to the presence of phyllosilicates and carbonates, respectively.
In addition, at some specific points, the band at 3.06 μm is found indicating the presence of ammonium-bearing compounds.
The Raman spectra acquired on the two particles are characterized by a high fluorescence background and by the presence of
the Raman D and G-bands related to the presence of poorly ordered carbonaceous matter. The spectral parameters derived
from the mathematical fitting of the acquired spectra as band positions, and band intensity ratio do not differ significantly
between the two particles. Raman analysis identifies dolomite as the most common carbonate on both particles.
The interpretation of spectral data acquired by both particles is currently in progress. However, at the moment there do notappear to be notable differences in spectral terms (VIS-NIR and Raman) between the two particles coming from the twodifferent sampling sites.
The two samples (A0198 and C0091) are characterized by a generally similar composition in terms of phase abundance andcomposition. Energy Dispersive X-ray spectroscopic (EDX) data obtained using the FE-SEM confirmed the presence of
hydrated silicates, sulfides (Ni-rich and Fe-rich), carbonates, fosfates, and oxides (mainly magnetite). Sulfides form
dominantly euhedral grains (up to 5 µm in size), whereas oxides form submicrometric framboid, platy, or columnar structures.
The internal distribution of silicates, sulfides, and oxide in the interior of the two samples, as revealed by XRM data, is rather
homogeneous. Notably, sample C0091 displays a slightly smaller grain size and a slightly higher porosity compared to particle
A0198.
Conclusions
The notable similarities of the spectra of some Ryugu samples with Ceres' average spectrum [18] sparked scientific curiosity.
To date, interpretation of remotely sensed data coupled with spectroscopic investigation of analogs has not enabled a fullunderstanding of the mechanisms of ammonium enrichment and the nature of the mineral assemblage hosting ammonium on
the surface of C-type objects. Furthermore, studies on meteorites have not provided morphological and compositional
information on the mineral phases that preceded the alteration of their progenitor body.
Therefore, we consider that spectroscopic measurements and nanoscale mineralogical investigations that we are conducting on
the samples returned from Ryugu represent a unique opportunity to definitively establish the link, if any, between ammonium
and the mineralogy of this type of object.
References[1]Yada, T. et al. (2021) Nat. Astron.; [2] Watanabe, S. et al. (2019) Science; [3] Kitazato, K. et al. (2019) Science; [4]Kitazato, K. et al. (2021) Nat. Astron.; [5] De Sanctis, M.C. et al. (2011) Space Sci. Rev.; [6] De Sanctis, M.C. et al. (2015)
Nature; [7] Tachibana, S. et al. (2022) 53rd LPSC, #1265; [8] Bi-bring, J.-P. et al. (2017) Astrobiology; [9] Pilorget, C. et al.
(2022) Nat. Astron.; [10] Kebukawa, Y. et al. (2022) 53rd LPSC, #1271; [11] King, T.V. et al. (1992) Science; [12]Ammannito, E. et al. (2016) Science; [13] Ferrari, M. et al. (2019) Icarus; [14] De Angelis, S. et al. (2021) J. Geophys. Res.
Planets; [15] De Sanctis, M.C. et al. (2016) Nature; [16] Raponi, A. et al. (2019) Icarus. [17] Coradini, A. et al. (2011) EPSCDPS Joint meeting, #1043. [18] Raponi, A. et al. (2021) Life.

Speciation of various elements using scanning transmission/fluorescnece X-ray microscopy(STXM/SFXM) and bulk XANES analysis related to aqueous environment
in the Ryugu parent body
Takahiro Kawai1, Keisuke Fukushi2, Hiroki Suga3, Masayuki Uesugi3, Shohei Yamashita4, Ryoichi Nakada5, Mizuho Koike6,
Hideto Yoshida1, Masaki Ohura7, Megumi Matsumoto8, Tomoki Nakamura8, Yasuhito Sekine,9 and Yoshio Takahashi1*(*Presenting author)
1
Department of Earth and Planetary Science, Graduate School of Sceince, The University of Tokyo, 2Institute of Nature andEnvironmental Technology, Kanazawa University, 3Japan Synchrotron Radiation Research Institute (JASRI), 4photon Factory,
Institute of Materials Structure Science, High-Energy Accelerator Research Organization (PF, IMSS, KEK), 5Kochi Institutefor Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 6Department of Earth andPlanetary Systems Science, Hiroshima University, 7RIKEN SPring-8 Center, 8Dept. of Earth Sciences, Tohoku University,
9
Earth-Life Science Institute, Tokyo Institute of Technology
The parent body of the C-type asteroid Ryuguu is thought to have been rich in volatile elements and abundant in liquidwater, making it an important research target for the origin of water and organic matter on Earth. The water caused various
alteration in the surrounding minerals, resulting in layered silicates such as smectite (saponite) and serpentinite being the main
constituent minerals of the Ryugu (Nakamura et al., 2023). In this process, the organic matter of the Ryuguu parent body also
underwent chemical reactions and a wide variety of organic matter was synthesised (Naraoka et al., 2023). It is particularly
important to obtain information on the water environment during the aqueous alteration, as the products of chemical reactionsof organic matter in water depend on the pH and redox potential (Eh) of the water. In this study, speciation of various elements
including iron (Fe), magnesium (Mg), calcium (Ca), and carbon (C) was investigated using scanning transmission X-ray
microscopy (STXM) and bulk X-ray absorption near-edge structure (XANES) analysis in the soft X-ray region related to theaqueous environment in the Ryugu parent body. For the elements with conentrations below the detection limit of STXM,
scanning fluorescnece X-ray microscopy (SFXM), newly developed in SPring-8 and Photon Factory was applied such as
nitrogen (N) and sodium (Na). The speication of these elements in saponite is particularly important, since the Fe oxidaiton
state and chemical composition within the interlayer of the saponite can indciate Eh-pH condition of the Ryugu water.
The Fe(II)/Fe(III) ratio in the octahedral structure of saponite was conducted by STXM. Based on our laboratory
experiments, dithionite reduction of natural Fe-bering saponite corresponding to Eh range from -0.47 to -0.66 (V) at pH = 7
shows the Fe(II)/Fetotal ratio around 0.55. The incomplete reduction by dithionite reveals that Fe(II)-bering saponite is a strong
reductant. Assuming that the relationship between the Fe(II)/Fetotal ratio and Eh of nontronite in Gorski et al. (2013) is similar
to that of saponite, the Fe(II) /Fetotal ratio greater than 0.68 measured by STXM indicates that the Eh was less than -0.45 (V).
On the other hand, because saponite has a negative charge in its layered structure, cations from the aqueous phase areadsorbed between the saponite layers during aqueous alteration. In this case, as shown by Fukushi et al. (2019), which cations
are retained in the interlayer depends on the concentration of various cations in the coexisting aqueous phase and theselectivity coefficient K. Therefore, the cation composition in the water layer at the time of aqueous alteration can be estimatedfrom the interlayer cation ratio determined by various analytical methods. In this processes, speciation of Na, K, and Ca wereconduted to obtain their fractions retained in the interlayer. The comparison of the Al content in saponite enables us to estimate
the Mg content in the interlayer. Contents of these cations with assumptions of dissolved silica etc. were used to construct an
Eh-pH diagram of Mg. We have estimated pH range that can explain the presence of both saponite and dolomite, which arewidely distributed in the altered crust in the Ryugu particles. The pH range estimated by the method was pH from 7.8 to 10.
Although the range is somewhat wide, the range is consistent with the results suggested in Nakamura et al. (2022).
The cmbination of Eh around -0.45 (V) and the alkaline pH range estimated above showed that the water was highly
reducing, which reveals that H2 and CH4 were present in the Ryugu water if we assume the equilibrium condition. Such analkaline condition is suitable for the polymerisation of amino acids (Kitadai and Maruyama, 2018).
References: Fukushi K. et al. (2019) Semiarid climate and hyposaline lake on early Mars inferred from reconstructed waterchemistry at Gale. Nat. Commun. 10, 1–11.; Gorski C. A. et al. (2013) Redox properties of structural Fe in clay minerals: 3.
Relationships between smectite redox and structural properties. Environ. Sci. Technol. 47, 13477–13485.; Kitadai N. andMaruyama S. (2018) Origins of building blocks of life: A review. Geosci. Front. 9, 1117–1153.; Nakamura T. et al. (2023)
Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples. Science 379, eabn8671.;
Naraoka H. et al. (2023) Soluble organic molecules in samples of the carbonaceous asteroid (162173) Ryugu. Science 379,
eabn9033.

Investigating the organic compounds in the asteroid Ryugu
Imene Kerraouch1*, Rhonda Stroud1, Larry Nittler2, Cassandra Kraver2, Jens Barosch3,4 and Jianhua Wang3
Buseck Center for Meteorite Studies (BCMS), Arizona State University, USA; 2School of Earth and Space Exploration(SESE), Arizona State University, USA; 3 Earth and Planets Laboratory, Carnegie Institution for Science, USA; 4 Department ofGeoscience, University of Wisconsin-Madison, USA. *ikerraou@asu.edu
1

Organic compounds in meteorites provide insights into the carbon chemistry present in the interstellar medium and solar nebulaand on their alteration on the parent bodies. Further, delivery of these organic compounds could have contributed to Earth’s
habitability and life. However, studying these compounds in meteorites is complicated by their exposure to terrestrial organic
contamination after entering the Earth's atmosphere. As such, one of the goals of the Hayabusa2 sample return mission (asteroid(162173) Ryugu) is to understand the nature, origin, and evolution of organic compounds in the early solar system but fromsamples free of terrestrial organic contamination. Here, we examine further samples from asteroid Ryugu that were collectedduring the first touchdown (Chamber A, samples A0079 and A0169; allocated in first Ryugu AO). The goals of our research are
to understand diversity, origin, and formation mechanisms of the macromolecular material that dominates Ryugu organics, aswell as the secondary processes involved in their modification, such as heating and aqueous alteration.
Fragments of the two Ryugu samples up to a few 10s of microns in size were pressed
into Au foils for H, C, and N isotope analysis with the Carnegie NanoSIMS 50L ion
microprobe. We used a ~0.4 pA, ~100-nm Cs+ primary beam and acquired data for C
and N isotopes, including 12C2, 12C13C, 12C14N, and 12C15N, as well as 16O, 32S, andsecondary electrons. The prepared samples were then analyzed for 1H, D, and 12C andsecondary electrons with a slightly more intense primary beam. C-rich regions ofinterest (ROIs) were defined in the C-N images and subsequently located and analyzed
in the H-D images.
We have analyzed a total area of ~9,000 m2 across the two samples. Data reduction isin progress. The majority of C-rich ROIs appear rounded in the ion images and range
from ~100 to 900 nm with some to up to a few µm (e.g., Fig.1). Consistent with previous
measurements [2-6], our data shows that the organic material is on average enriched in
D and 15N with most ROIs having compositions consistent within error with averagevalues of D of a few 100 ‰ and 15N~ +50‰. However, one lath-like rectangulargrain was identified in a particle within A0079 (Fig. 1), similar in shape to a grainpreviously reported in Chamber C [5; Fig.3], but larger. This 4.5 × 1 μm grain has anextreme isotopic composition: δD ≈10,000 ‰ and δ15N ≈ +800‰. In order to clarify
the nature and origin of this unusual grain and other select C-rich ROIs, we are currently
extracting focused ion beam (FIB) lift-out sections of D and 15N hotspots. The FIB
sections will be studied with transmission electron microscopy, scanning transmission
electron microscopy, energy dispersive spectroscopy and electron energy loss
spectroscopy at Arizona State University. Results from these investigations will bepresented at the symposium.

Figure 1. (a) Secondary electron (SE)image of a Ryugu particle fromchamber A (A0079) pressed into gold
foil. (b) D and 15N-enriched lath-like(whisker) detected in same particle.

References: [1] Huss G. R. and Draine B. T. 2006. Highlights of Astronomy 2: 353–356. [2] Busemann H. et al. 2006. Science
312, 727–730. [3] Nittler L. R. et al. 2019. Nat. Astron. 3, 659–666. [4] Nittler L. R. et al. 2018). GCA 226, 107–131. [5] Barosch
J. et al. 2022. Abstract#2050. 53rd LPSC; [6] Yabuta, H. et al. 2023. Science 379, eabn9057.

Constraining Ryugu’s earliest fluid composition by the analyses of phosphates
Nicolas David Greber1,2, Johanna Marin-Carbonne3, Anne-Sophie Bouvier3, James Greenwood4, Thomas Bovay3, Martin
Robyr3, Cristina Martin Olmos3
1
Muséum d’histoire naturelle de Genève, Route de Malagnou 1, CH-1208 Genève, Switzerland
2
Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, 3012 Bern, Switzerland
3
Institute of Earth Sciences, University of Lausanne, CH1015 Lausanne, Switzerland
4
Department of Earth & Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, Connecticut 06459,
USA
Volatile elements and compounds like F, Cl, S, H2O and CO2, indisputably exert a strong influence on the nature and evolutionof (exo)planets, of which water is arguably the most prominent for the habitability of the Earth. Most volatiles were likely
brought to Earth by carbonaceous chondrite-like material, including asteroids, making the undisturbed material of Ryugu key
samples to improve our understanding of the distribution of water in our solar system and the origin of water on Earth.
The water concentration in CI chondrites is distinct from that of Ryugu (13 to 20 wt% compared to 6.8 wt%, respectively;[1,2]), which might be explained (i) by loss of water from Ryugu during the disruption of the parent body, (ii) impact heating,(iii) that CI chondrites derive from parent asteroids with higher water content than Ryugu, or (iv) that CI chondrites got
contaminated by water during their residence time on Earth [2-4]. Importantly, the apatite grains found in Ryugu likely
originate from the aqueous alteration of Ryugu that predates the events that might have lead to the loss of some of Ryugu’s
water inventory (see points i and ii, [5,6]). Thus, measuring the chemical and isotopic compositions (e.g. H, O, etc) of these
apatites will likely help to better constrain the initial composition of Ryugus water, prior to its disruption, which is the aim ofdifferent research projects currently ongoing.
We will present the developed method on how we measured the H-isotopic composition of the apatites in Ryugu and discuss
this preliminary results in the context of the initial dD value of Ryugu’s water.

References[1] Palme, H., and J. Zipfel. 2022. Meteoritics & Planetary Science 57.2:317-333.
[2] Yokoyama, et al. 2022. Science 379.6634:eabn7850.
[3] Ito, et al. 2022. Nature Astronomy 6.10:1163-1171.
[4] Kurosawa, et al. 2021. Communications Earth & Environment 2.1:146.
[5] Nakamura, et al. 2022. Proc. Jpn. Acad. Ser. B 98
[6] Sugita, et al. 2019. Science 364.6437:eaaw0422.

Interpreting the thermal alteration history from organic matter in Ryugu samples
Queenie Hoi Shan Chan1*, Tomoki Nakamura2, Michael Zolensky3, Jangmi Han4, Mizuha Kikuiri2, Kana Amano2, Ashley
King5, Charlotte Bays1,5, Peter Krizan1, Natasha Almeida5, Megumi Matsumoto2, Akira Tsuchiyama6,7,8, Akira Miyake9, Junya
Matsuno9, Luis Carlos Colocho Hurtarte10, Rosario Brunetto11, Mark Burchell12, Vassilia Spathis12, Ming Chang Liu13 andJunko Isa14, and the Hayabusa2 initial analysis Core team.
1

Centre for Dynamic Earth and the Solar System (CeDESS), Department of Earth Sciences, Royal Holloway University of
London, Egham TW20 0EX, UK. 2Department of Earth Sciences, Tohoku University, Tohoku University, Sendai 980-8578,
Japan. 3NASA Johnson Space Center; Houston TX 77058, USA. 4Department of Earth and Atmospheric Sciences, University of
Houston, Houston TX 77204, USA. 5Planetary Materials Group, Natural History Museum, London SW7 5BD, UK. 6Research
Organization of Science and Technology, Ritsumeikan University, Kusatsu 525-8577, Japan. 7Chinese Academy of Sciences(CAS) Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics andMaterials, Guangzhou Institute of Geochemistry, CAS, Guangzhou 510640, China. 8CAS Center for Excellence in Deep Earth
Science, Guangzhou 510640, China. 9Division of Earth and Planetary Sciences, Kyoto University, Kyoto 606-8502, Japan.
10
Diamond Light Source, Didcot OX11 0DE, UK. 11Institut d’Astrophysique Spatiale (IAS), Université Paris-Saclay, Orsay
91405, France. 12Centre for Astrophysics and Planetary Science, School of Physics and Astronomy, University of Kent,
Canterbury CT2 7NZ, UK. 13Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, USA.
14
Earth-Life Science Institute, Tokyo 152-8550, Japan.
Introduction: The Hayabusa2 mission visited the near-Earth Cb-type asteroid (162173) Ryugu and has returned to Earthwith the surface material of Ryugu. Ryugu is an airless rubble pile asteroid exposed to space weathering [1]. Near infrared
remote observations recorded an absorption feature at 2.72 μm indicating the presence of OH–bearing hydrous components.
However, the 2.72 μm feature is weak, suggesting that Ryugu was once organic- and water-rich and subsequently dehydrated
by a brief period of surficial heating. This feature has also been observed in “thermally metamorphosed carbonaceouschondrites”, “CI-/CM-like”, or “CY” chondrites [2, 3]. Initial examination of the returned samples did not identify any
significant heating at >150 °C [4, 5]; however, amino acid analyses suggested similarities to thermally-altered meteorites on
the grounds of the predominant straight-chain n-ω-amino acid abundances [6]. It remains unclear as to what caused thenonconformal interpretations of the thermal alteration history of Ryugu.
Here we investigate the alteration history of Ryugu by comparing the organic composition of fresh Ryugu samples to thatof naturally and experimentally heated chondritic meteorites. This study describes a coordinated effort in analysing organic
matter in Ryugu samples using micro–x-ray computed tomography (μ-CT), micro-Raman spectroscopy, focused ion beam
(FIB), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), micro-X-ray diffraction (μXRD), scanning transmission X-ray microscopy (STXM), X-ray absorption near edge structure (XANES), and synchrotron
radiation-based X-ray computed tomography (SR-CT).
Samples and Analytical Techniques: We studied Ryugu samples allocated during the Hayabusa2 preliminary
examination (A0063-FC016, A0063-FC017, A0064-FO012, A0067-FC008, C0002-FC014, C0002-FC015, C0025-FC003,
C0033-FC003, C0046-FO003) and AO1 (A0009 and C0011), plus raw fragments of naturally long-term (CIs: Orgueil, Ivuna;
CMs: Murchison, Murray; CV: Allende; CRs: Grosvenor Mountains 95577; OCs: Yamato (Y)-74191, Queen Alexandra
Range 93010) and short-term heated meteorites (Belgica-7904, Jbilet Winselwan, Y-793321, Y-86720, Y-982086) [7, 8]. We
also analysed samples of Murchison, Murray and Orgueil experimentally heated to 300, 400, 500, 600, 700 and 900 °C for 1,
10, 50, 100, 500 and 1000 hours. Raman analyses were conducted using a Jobin-Yvon Horiba LabRAM HR Raman
microprobe with a 514 nm laser for which the power was maintained at <100 μW at the sample surface. The mineralogy of the
raw Ryugu samples was characterised using low-voltage SEM-EDS (FEI Quanta 650) and μ-XRD. We identified regions ofinterest (ROIs) within A0009 and C0011 by conducting μ-CT analysis using a cabinet-based industrial Zeiss Xradia Versa 520
CT system. Targeted ROIs were picked using sterile tools, pressed into indium, and prepared into electron-transparent sections(~100 nm thick) mounted on TEM Cu grids using a FEI Quanta 3D 600 dual beam FIB-SEM, which were studied by STXMXANES to determine the organic composition. Euhedral sulphide crystals were lifted and mounted on W-needles by the FIBSEM, and potential fluid inclusions within them were then located by SR-CT conducted at SPring-8 BL47XU at the X-ray
energy of 7 keV.
Results and Discussion: Increased heating of carbonaceous materials results in a transition from amorphous to graphitic
carbon, and such ordering is traceable using Raman spectroscopy as a cosmothermometer [9]. Raman spectroscopic analysis of

the Ryugu samples indicates significant heterogeneity (Figure 1), evident by Raman spectral features that are comparable tothe organic matter in both relatively unheated primitive chondrites and those that experienced short duration heating like Y793321, a Stage II heated chondrite [10].
The Raman spectral features of the organic matter inmost of the Ryugu samples are similar to those observed
from CIs, consistent with previous studies [11]. However,
localised areas within several Ryugu samples show awider G band, comparable to organic matter processed byshort duration heating. The Raman features of the organic
matter in broad areas within A0009, A0064 and C0011
clearly deviate from that observed from the other Ryugu
samples and Orgueil, with significantly lower D band
positions and D band widths that are comparable to
Figure 1. Comparison of the Raman D and G band parameters of Ryugu
chondritic organics that had been heated at elevated samples (yellow symbols), and naturally short-term heated samples
temperatures [9], and larger G band widths that are not (black symbols; Stage II CCs peak heating temperature ~250–500°C;
observed in naturally metamorphosed chondritic Stage IV CCs >750°C). Γ=Full width half maximum; ω = Peak location.
meteorites (Figure 1). These trends are similar to thoseexhibited by astromaterials heated by short-term heating, like interplanetary dust particles [12] and some meteorites [13]. The
Raman spectra of A0009, A0064 and C0011 are similar to those of Orgueil experimentally heated to 300 °C for 500 h.
Analysis of A0064 by SEM-EDS and μ-XRD shows
the presence of hydrated phyllosilicates, suggesting that theparticle did not experience significant heating above ~300–
400 °C. Moreover, the SR-CT data validated the μ-CT scans,and indicate that C0011 contains a sulphide grain hosting an
inclusion with X-ray attenuation that is clearly distinct fromair (Figure 2). Previous studies have revealed H2O and CO2
within such inclusions [14], suggesting that they have notbeen metamorphosed after aqueous alteration. Analysing Figure 2. SR-CT images of a sulphide grain picked from C0011.
these more “evolved” particles with STXM-XANES helped
us understand the organic structure corresponding to the Raman features. C-XANES spectra of A0009 and C0011 indicate thepresence of aromatic or olefinic groups (C=C) at ~285 eV and carboxylic groups (COOH) at ~288.5 eV within the matrix
associated with carbonate grains (CO3 absorption at 290.3 eV). While thermally stable oxygenated functional groups wereobserved in short term (impact induced) heated meteorites [15], the association of the organic matter with carbonates iscomparable to the carboxylic-rich diffuse organic matter in CM and CI chondrites [16]. Based on our coordinated investigation,
we have drawn two possible scenarios that can explain our observations: (1) some carbonaceous matter in Ryugu had
experienced post aqueous alteration short duration heating (impact induced and/or solar irradiation), resulting in the presenceof thermally stable oxygenated moieties like furan and phenol that were formed via dehydration and cyclisation ofpolyalcohols. These “evolved” materials were subsequently disrupted and redistributed by impacts, thermal fatigue, and/or
mass wasting processes [17], intermixed with fresh, undisturbed and pristine Ryugu materials. Alternatively, (2) the formationof the macromolecular organic matter occurred at the final stages of aqueous alteration in low-temperature, highly oxidizing
fluids, e.g., fluid with OH radicals contributing through H2O2 dissociation [18], co-precipitating carboxylic enrichedcomponents in the immediate vicinity of carbonate.
Acknowledgements: We are extremely grateful to the Astromaterials Science Research Group (ASRG) of ISAS/JAXA
for providing the Ryugu samples.
Reference: [1] Noguchi, T., et al. Science, 2011. 333: p. 1121-1125. [2] Kitazato, K., et al. Science, 2019. 364: p. 272275. [3] Vilas, F. The Astronomical Journal, 2008. 135: p. 1101. [4] Naraoka, H., et al. Science, 2023. 379(6634): p. eabn9033.
[5] Yabuta, H., et al. Science, 2023. 379(6634): p. eabn9057. [6] Parker, E.T., et al. GCA, 2023. 347: p. 42-57. [7] Tonui, E., etal. GCA, 2014. 126: p. 284-306. [8] Nakamura, T. JMPS, 2005. 100: p. 260-272. [9] Busemann, H., M.O.D. Alexander, and
L.R. Nittler. MAPS, 2007. 42: p. 1387-1416. [10] Nakamura, T. Earth and Planetary Science Letters, 2006. 242(1): p. 26-38.
[11] Yokoyama, T., et al. Science, 2022. 379(6634): p. eabn7850. [12] Chan, Q.H.S., et al. MAPS, 2020. 55(6): p. 1320-1348.
[13] Quirico, E., et al. GCA, 2014. 136: p. 80-99. [14] Zolensky, M., et al., Hayabusa Symposium. 2023. [15] Yabuta, H., et al.
MAPS, 2010. 45: p. 1446-1460. [16] Le Guillou, C., et al. GCA, 2014. 131: p. 368-392. [17] Morota, T., et al. Science, 2020.
368(6491): p. 654-659. [18] Cody, G.D. and C.M.O.D. Alexander. GCA, 2005. 69: p. 1085-1097.

First direct detection of large aromatic molecules on asteroid (162173) Ryugu sample C0083 andA00145: an interstellar heritage
Hassan Sabbah1, Ghylaine Quitté1, Karine Demyk and Christine Joblin11IRAP, Université Toulouse III – Paul Sabatier, CNRS, CNES, 31028 Toulouse Cedex 4, France
Although meteorite analysis has revealed various types of pre-solar grains, the presence of large polycyclic aromatichydrocarbons (PAHs) of interstellar origin has not been firmly established. Here we present a search for these compounds in
the C0083 and A00145 grains from the Ryugu asteroid. The experiment takes advantages of the ultra-sensitivity of the
AROMA (Astrochemistry Research of Organics with Molecular Analyzer) setup to target these species.
The AROMA setup was developed specifically for studying the carbonaceous molecular composition of meteorites and cosmic
dust analogues [1]. It consists of a laser desorption ionization (LDI) source combined with a segmented linear quadrupole ion
trap (LQIT), all connected to an orthogonal time-of-flight mass spectrometer (oTOF). The ion source is at a low pressure of 106
mbar and can be operated using a two-step laser desorption ionization scheme. This L2MS analysis provides ultra-sensitivity
for PAHs and fullerenes as demonstrated in our earlier study [2]. This laser technique also requires little or no sample
preparation and uses very little material.
Subsamples of the two Ryugu grains have been isolated and used either as bulk or crushed in the form of powder to improvesensitivity. The data obtained are compared to previous AROMA analyses of carbonaceous chondrites (CCs) such as
Murchison and Orgueil. This reveals a number of peculiarities in the distribution of PAHs in Ryugu grains. In particular wereport the presence of PAHs containing as much as 50 carbon atoms, which can be considered as interstellar candidates.
Moreover, we have identified aromatic compounds that incorporate nitrogen (N) and oxygen (O) heteroatoms, with carbon
atoms extending up to 48. These findings impact our view on the complexification of organic matter in the cycle of matterfrom the interstellar matter to the Solar System. It also motivates the research for these large compounds in other CCs

References[1] Sabbah et al. 2017. The Astrophysical Journal, 843, 34. [2] Sabbah et al 2022. The Astrophysical Journal, 931, 91.

FIB Tomography-STXM-TEM on organic material from Hayabusa-2 grain A0083.
H. G. Changela1, Y. Kebukawa2, L. Petera1, M. Ferus1 E. Chatzitheodoridis3, L. Nedjl4, R. Nebel1, Z. Hlavenkova5, J.
Moravcova5, P. Krepelka5, R. Holbova5, J. Novacek5, T. Samoril6,7, K. Sobotkova6, H. Tesarova6 and D. Zapotok8
1 J’Heyrovski Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czechia. 2 Tokyo Institute of Technology,
Tokyo, Japan. 3 National Technical University of Athens, Greece. 4 Bruno University of Technology, Czechia. 5 Central
European Institute of Technology Masaryk University, Brno, Czechia. 6 Central European Institute of Technology Nano, Brno,
Czechia. 7 TESCAN GROUP a.s., Brno, Czechia. 8 TESCAN USA Inc, Pennsylvania, USA. Email: changela@unm.edu
Introduction The success of the Hayabusa-2 mission provides unique insight into prebiotic evolution from a known asteroid
free from terrestrial contamination. Asteroid 16273Ryugu (Ryugu here on in) is of CI (Ivuna-type) composition, lacking any
distinct chondrules and calcium aluminium inclusions, and is composed mainly of secondary minerals including phyllosilicate,carbonates, (Fe, Ni) sulphides, Fe-oxides and phosphates [1]. Organic material (OM) also pervades Ryugu, characteristic of
OM found in primitive chondrite matrices. Micron to submicron organic particles (OPs) – macromolecular organic objects
completely surrounded by inorganic material – make up the major mass fraction of OM [e.g. 2], consistent with insolubleorganic matter (IOM). A volumetrically diffuse organic component aromatic-poorer and carboxylic-richer than OPs foundwithin chondritic hydrated silicates [3] also occurs in Ryugu [4]. This study is on a grain from the 1st touch-and-go (TAG) site
on Ryugu, characterising the distribution, functional chemical variation and mineral setting of OM in situ.
Samples & Methods Grain A0083 (Radegast here on in) is a 1.3 and 1.7 mm grain from Chamber A of the Hayabusa-2
collector TAG site. Radegast was prepared and analyzed taking an approach of minimal damage and material loss forcharacterisation. Radegast was picked up with vacuum tweezers and placed on a clean Au base with an ~2 mm divot, mounted
on an Al stub. An ~1.5 mm circular hole in clean Al foil was placed over the top of Radegast and fastened at the edge of thestub, exposing the grain out of the hole and securing it. This has the advantage that the grain can be turned over by lifting thefoil for any further characterization whilst leaving the grain intact. Focused Ion Beam (FIB) ~100 nm lamella of Radegast wereprepared for Scanning Transmission X-ray (STXM) and Transmission electron Microscopy (TEM). The TESCAN AMBERX
and LYRA3 at TESCAN GROUP and the Central European Institute of Engineering & Technology (CEITEC)-nano,respectively, were used to compare the effects of Xe+ plasma FIB with Ga+ FIB lamella preparation on the STXM
measurements of OM in the samples. To minimize sample information losses by destruction from the traditional FIB lamella
sample preparation, FIB tomography was performed from the edge of the grain during milling prior to lift-out. Grains of Ivuna
were also embedded in molten S for ultramicrotome using methods in [5]. 110 nm samples were cut using a Leica UC7 at
CEITEC-Muni to compare the STXM measurements between Xe-, Ga- FIB lamella and microtome samples. Scanning
Transmission X-ray Microscopy (STXM) measurements were made at BL 19A at the Photon Factory, Japan. S/TEM was
performed with the CEITEC-MUNI Thermofisher Talos F200C, and the J’Heyrovski Institute’s JEOL 2100.
Ga+

a.

b.

Xe+

3D

30 μm

20 μm

100 µm10 µm

c.

500 μm
10 μm

20 μm

Phyl

5 µm

Figure 1. BSE images of particle A0083 (Radegast). (a) Entire image of Radegast. Insets show various phases on the top of the particle. Blueand purple are Fe-Sulphides (probably hexagonal pyrrhotite) Yellow is Fe-oxides (magnetite). Pink is a mixture of minerals. Green rectangle
shows the region of tomography from the top edge of Radegast. (b) Tomography and Lamella liftout regions. Inset show the milled regions
for tomography and lamella liftout made between Ga+ (LYRA3) and Xe+ (AMBERX) FIB instruments. (c) A Coarse grained organic particle(arrowed) from 1st cross section of tomography volume.

Results & Discussion Radegast displays CI composition similar to samples from both TAG sites, suggesting widespread
alteration across the asteroid. Organic particles are mostly submicron with IOM morphology. Some coarser OPs identified in
the tomography completely surround phyllosilicate, suggesting post-formation of the primary mineralogy within them (Fig. 2).
Slice 240

Slice 248

Slice 255

Slice 283

Slice 269

Slice 292

Slice302

OP

Phyllosilicate

1 µm

Figure 2. FIB Tomography slices of a coarse-grained organic particle in Radegast.

Organic particles and diffuse OM are consistent between FIB and microtome samples of Ivuna (diffuse OM in microtome
samples have not been previously reported), implying that both Ga+ and Xe+ FIB preserve the functional chemistry of OPs
and diffuse OM (Fig. 3). Carbon-XANES shows that individual OPs in closer proximity to one another are more equilibrated,suggesting that the alteration recorded in the grain was a common process evolving them. They have aromatic-rich, 3-peak
spectra similar to the ‘aromatic’ particles in [4]. Notably, OPs in Ivuna are aromatic poorer, with lower aromatic/ketone ratios
than those in Radegast and other Ryugu samples. Aromatic-rich OPs are however in higher abundance in the CR1 GRO 95577[2] and Orgueil [3] than the type 2/3 carbonaceous chondrites. Diffuse OM (aromatic-poorer and aliphatic/carboxylic-richer
OM than OPs) in Radegast is also more similar to diffuse OM found in Ivuna (Fig. 3) and GRO 95577 [2], with higher
carboxyl/aromatic peak ratios than type 2/3. It is also similar by being in phyllosilicate rather than amorphous hydrated
silicates found in type 2/3 chondrites. SEM and TEM (Fig. 5) shows coarse and finer domains of phyllosilicate. Diffuse OM
occurs in both domains of phyllosilicate but is less concentrated in the coarse domains than the finer ones that are alsointermixed mostly with Fe and Fe,Ni-rich sulphides (Fig. 3a). HRTEM shows the coarse domains as mixed layers of serpentine
and smectite, consistent with previous studies [6].

Figure 3. STXM-TEM on Radegast. (a) HAADF
image of Xe+ prepared lamella. Inset is magnified
region where the C-XANES Stack was made, showing
a calcite grain adjacent to an OP. (b) C-XANES of
OPs and diffuse OM in Ivuna and Radegast. The OPin (a) is pink. Note the higher aromatic/ketone ratio of
OPs in Ryugu than in Ivuna.

Conclusion Organic material in Radegast evolved into aromatic-rich organic particles and aliphatic/carboxyl-rich diffuse OM
by alteration on Ryugu, similar to those found in type C1 planetary materials.
References [1] Nakamura T. et al. 2022 Science 379: eabn8671. [2] Changela. H. G. et al. 2018 Meteoritics & Planetary
Science 53:1006-1029. [3] Le Guillou C. et al. 2014 Geochimica Cosmochimica Acta 131: 368-392. [4] Yabuta H. et al. 2023
Science 679: 6634. [5] Noguchi T. et al. 2020 Life 10(8):135. [6] Ito M. et al. 2022 Nature Astronomy 6(10): 1-9.
Acknowledgements This research was funded by the Czech Science Foundation Project Reg. No. 21-11366S with financial support by
ERDF/ESF Centre of Advanced Applied Sciences (CZ.02.1.01/0.0/0.0/16_019/0000778). We acknowledge CF CryoEM of CIISB, Instruct-CZ
Centre,supported

by

MEYS

CR

(LM2023042)

andEuropean

Regional

Development

Fund-Project

UP

CIISB

(No.

CZ.02.1.01/0.0/0.0/18_046/0015974). We thank Takis Theodossiou of the Greek Meteorite Museum for the curation of the Ivuna meteorite.

New view on the paleomagnetic record of samples from asteroid Ryugu
1

C. Maurel1, J. Gattacceca1, M. Uehara1
CNRS, Aix Marseille Université, IRD, INRAE, CEREGE, Aix-en-Provence, France

The JAXA Hayabusa 2 mission returned ~5 g of material from the C-type asteroid Ryugu. Ryugu
material contains abundant magnetite and pyrrhotite, formed during aqueous alteration on its
parent body. The timing of aqueous alteration is not yet well constrained, with estimates ranging
between 1.8 and 6.8 Myr after CAI formation (Yokoyama et al., 2022; McCain et al., 2023). Given
these uncertainties, aqueous alteration on Ryugu’s parent body may have occurred during the
lifetime of the solar nebula magnetic field (i.e., up to ~5 Myr after CAI formation; Weiss et al.,2017). Magnetite and pyrrhotite may therefore carry a chemical remanent magnetization reflecting
the intensity of this field.
Rock magnetic and paleomagnetic data of Ryugu samples were recently published (Nakamura etal. 2022; Sato et al., 2022). The authors measured the NRM of two samples (0.425 mg and 1.556mg) and demagnetized the NRM using alternating fields (AF). They identified stable remanencecomponents in both samples up to 24 mT and 32 mT, respectively, which they interpreted as
evidence that Ryugu material experienced a 41- to 390-µT solar nebula field.
We conducted a new paleomagnetic investigation of two other Ryugu samples with mass 0.8 mg
and 20.8 mg. Data are very consistent among our two samples, but their mass-normalized NRM
intensities are 20 to 100 times weaker than the published ones. NRM demagnetization data exhibit
a poorly defined low-coercivity component up to ~8 mT, but become completely erratic at higher
AF field steps. A similar demagnetization behavior is found after applying anhysteretic remanent
magnetizations (ARM) acquired in bias fields up to 10 µT. For ARM bias fields of 20 µT and
greater, we can identify a component of the magnetization in the coercivity range 10-50 mT.
Although further analyses are being conducted, this favors the idea that the samples experienced
magnetic fields < 17 µT in intensity, assuming the sample acquired a chemical remanent
magnetization. This upper limit is compatible with both (i) the nebula field intensity estimatedfrom other meteorites with similar age of the NRM, and (ii) the absence of field.
We suspect that the samples used by Nakamura, Sato and colleagues may have been contaminatedby exposure to strong magnetic fields up to ~20 mT. We will discuss how such a contamination
can be identified using measurements that are non-destructive for the NRM. This highlights theneed for extreme caution to avoid magnetic contamination during handling of returned
extraterrestrial material. Our data show, however, that the samples were not remagnetized en masse
during sampling on the asteroid, in transit in the spacecraft or during curation preceding any
measurements.
We are very grateful to JAXA for the allocation of the Ryugu samples A0154 and C0005.

References
Yokoyama, T., et al. (2023) Science 379, eabn7850; McCain, K. A., et al. (2023) Nat. Astro. 7, 309-317;
Weiss, B. P., et al. (2017) Earth Planet. Sci. Lett. 468, 119-132; Nakamura, T., et al. (2022) Science 379,
eabn8671; Sato M., et al. (2022) J. Geophys. Res. Planets 127, e2022JE007405

Cosmogenic Radionuclide Records of Hayabusa Aggregate and Particle Samples
Kunihiko Nishiizumi1, Marc W. Caffee2, Keisuke Nagao3, Kees C. Welten1, Jozef Masarik4
Space Sciences Laboratory, Univ. of California, Berkeley, CA 94720-7450, USA., 2Dept. of Physics & Astronomy, Purdue
Univ., West Lafayette, IN 47907-2036, USA., 3Div. of Polar Earth-System Sci., KOPRI, Incheon 21990, Korea, 4Faculty ofMath. & Physics, Comenius Univ., SK-842 15, Bratislava, Slovakia

1

Hayabusa2 arrived at the C-type asteroid 162173 Ryugu in June 2018, and successfully collected surface samples from two
sampling sites, returning ~5.4 g of material to Earth on December 6, 2020. The surface samples stored in Chamber A werecollected by the 1st touchdown (TD) on Ryugu’s surface on February 21, 2019. A crater (diameter of ~14 m) on Ryugu’s
surface was made using a collision device - denoted “Small Carry-on Impactor (SCI)” - on April 5, 2019 [1]. The samples in
Chamber C were collected proximal to the north side of this artificial crater by the 2nd TD on July 11, 2019 and possibly containejecta from the crater [2]. Distance between TD1 and TD2 is ~820 m.
Our studies are based on the measurement of those nuclides produced in asteroidal surface materials by cosmic rays - bothsolar (SCR) and galactic cosmic rays (GCR). Cosmic-ray-produced (cosmogenic) nuclides are used to determine the durationand nature of the exposure of materials to energetic particles. Our goals are to understand both the fundamental processes on
the asteroidal surface and the evolutionary history of its surface materials. For Hayabusa2 samples, there are several specificquestions we aim to address: (1) are the Chamber C samples, collected during the 2nd TD ejecta deposits from the artificial crater,(2) if so, what is the original depth of each recovered sample in the Ryugu regolith, and (3) what is the surface exposure time,
mixing rate, and erosion/escape rate of Ryugu’s surface? To answer these questions, we were allocated and received particles
from Chamber A and Chamber C for measurements of cosmogenic radionuclides and noble gases as a part of initial analysis of
Ryugu. We have measured cosmogenic 10Be (t1/2 = 1.36 x 106 yr), 26Al (7.05 x 105 yr), 36Cl (3.01 x 105 yr), and stable noble
gases in those samples [3-5]. Based on noble gas analysis of ~2 dozen Ryugu samples, we found that cosmic ray exposure(CRE) ages of Chamber A (surface) samples, A0105, range from 2.9 to 7.5 Myr and Chamber C (sub-surface) samples, C0106,
range from 1.6 to 5.8 Myr based on 21Ne concentrations [3, 6]. We also found that four C0106 particles were exposed at depthof ~50, 110, 130, and 145 g/cm2 respectively and had different CRE ages based on cosmogenic nuclide measurements [3, 5].
To further study of the exposure condition of Ryugu surface materials, we obtained one grain, A0130, from Chamber A and3 grains, C0012, 0162, and 0182 from Chamber C. In addition, we obtained two aggregate samples, A0221 and C0212, inorder to determine average exposure ages and depths for both Chamber A and C samples. As shown above, each grain had
different exposure histories (age and depth). This is similar to what we found for exposure histories of individual grains oflunar core samples. While cosmogenic radionuclides of lunar bulk soils show smooth depth profiles, the measured radionuclide
concentrations of individual rock fragments at the same depth show deviations from the smooth depth profiles [7].
Each sample was gently crushed by a mortar and pestle made from sapphire and then divided into two fractions, one fraction
for cosmogenic radionuclides (this work) and one for noble gases measurements [8]. The samples were individually transferred
to a small Al weighing boat and the masses were determined using an ultra-micro balance. For cosmogenic radionuclide
analysis, the sample was transferred to a Teflon bomb and dissolved with HF and HNO3 mixture in the presence of Be and Cl
carriers. After Cl was separated as AgCl for 36Cl measurements, a small analysis aliquot was taken for chemical analysis by
ICP-OES. Beryllium, Al, and Mn were separated by ion chromatography, using anion and cation ion exchange columns, andBe and Al were purified for AMS measurements. To serve as a baseline comparison, a few grains of the Orgueil CI chondrite
were analyzed using the same protocols. Beryllium-10 and 26Al AMS analyses were performed at PRIME Lab, Purdue
University [9]. Measured isotopic ratios were normalized by AMS standards [10, 11] and converted to radionuclide
concentrations (dpm/kg).
Chemical compositions in Ryugu samples measured by ICP-OES are shown in Table 1. Since sample sizes are slightly
larger than previous Ryugu initial analysis, data show less scatter. Bulk chemical compositions of samples from TD1 and TD2
determined using ICP-MS [12] are also shown in the table. Our analysis of A0221 and C0212 are in good agreement withanalysis of TD1 and TD2 samples determined by [12]. Noticeably, both our two samples and published analysis of TD1 andTD2 samples [12] were obtained from aggregate samples and not individual grains. Although [12] concluded that are no
systematic differences in chemical composition between the samples from TD1 and TD2 sites, our limited measurements indicatethat Ca is slightly higher and Fe is lower in TD1 samples than that of TD2.

Table 1. Chemical compositions in Ryugu samples and Orgueil CI chondrite.
Sample

Mg
(%)
9.32
10.84
10.54
10.74
10.81
9.36
10.77
10.69
10.42
7.37
9.63

A0130
A0221
C0012
C0012
C0162
C0182
C0212
Ryugu (TD1)*
Ryugu (TD2)*
Orgueil CI
Orgueil CI#

Al
(%)
0.94
0.90
0.91
0.91
0.90
0.84
0.98
0.86
0.90
0.64
0.60

K
(ppm)
720
520
600
580
570
400
550
520
600
440
530

Ca
(%)
1.45
1.69
1.09
1.18
1.08
0.95
1.18
1.63
1.37
0.60
0.76

Ti
(ppm)
520
530
460
490
570
510
510
480
470
340
-

Mn
(ppm)
1990
3040
2020
2340
2120
1510
2370
3000
2490
1380
1680

Fe
(%)
18.39
19.76
21.15
20.11
20.75
18.63
20.53
19.49
20.22
14.23
17.76

Co
(ppm)
540
560
600
560
560
520
590
550
590
400
540

Ni
(%)
1.13
1.20
1.31
1.21
1.26
1.13
1.26
1.18
1.22
1.18
1.04

*[12], #Previous measurement (unpublishd 2003)

Cosmogenic nuclide 10Be and 26Al concentrations in Ryugu samples are shown in Table 2 along with that of Orgueil CI
chondrite. Using the MCNP Code System [13], we calculated the GCR production rates of 10Be and 26Al by spallation reactions
for a body having a 2π geometry with Ryugu’s chemical composition [12]. Based on the comparison of the observed
radionuclide concentrations with model calculated 10Be and 26Al production rate depth profiles, assuming the radionuclide
concentrations in Ryugu are saturated, we obtained the first order estimation of exposure depth of each sample and shown in
Table 2. Based on those depths we calculated 21Ne production rates and calculated 21Ne CRE ages in each sample [8]. The
calculated exposure depths and CRE ages of each grain obtained by TD2 scatter, in similar fashion as previous works [3, 5].
The preliminary estimation of average exposure depth of aggregate sample A0221 is somewhat deeper than those of each grain
obtained from TD1. The depth range of aggregate sample C0212 collected by TD2 is estimated to be 110 - 140 g/cm2 basedon 10Be concentration. The 26Al concentration of C0212 indicates much shallow depth of 10 – 90 g/cm2. One possible
explanation is that C0212 contains a small amount of surface material that contains high SCR produced 26Al. The measurementof thermal neutron-capture produced 41Ca (t1/2 = 1.0 x 105 yr) – in progress - is critical to further constrain the exposure depth ofeach sample.
Table 2. Cosmogenic nuclide 10Be and 26Al concentrations in Ryugu samples and Orgueil CI chondrite.
1026
Sample
Mass
Be
Al
Depth
(mg)
(dpm/kg)(dpm/kg)(g/cm2)A0130
0.676
9.94 ± 0.29
29.2 ± 1.3
10 - 70
A0221
10.718
11.23 ± 0.10
27.4 ± 0.6
70 - 100
C0012
4.200
7.50 ± 0.10
24.3 ± 0.8
90 - 140
C0012
7.274
7.43 ± 0.15
23.3 ± 0.8
110 - 150
C0162
1.531
7.58 ± 0.21
24.6 ± 1.0
95 - 145
C0182
0.983
6.28 ± 0.15
25.3 ± 1.3
85 - 135
C0212
8.406
9.06 ± 0.09
29.3 ± 0.6
110 -140
Orgueil CI
6.000
14.91 ± 0.31
35.9 ± 1.2
Orgueil CI#
52.60
21.19 ± 0.36
40.4 ± 0.8#

Previous measurement (unpublished 2003)

Acknowledgments: We thank Hayabusa2 project team and Hayabusa2 curation members. Orgueil was obtained from
MNHN-Paris. This work was supported by NASA’s LARS program.
References:[1] Arakawa M. et al. (2020) Science. 368, 67-71. [2] Tsuda Y. et al. (2020) Acta Astronautica. 171, 42-54. [3] Nagao K. et al.
(2022) Meteor. Planet. Sci. 57, A337 #6320. [4] Nishiizumi K. et al. (2022) Lunar Planet. Sci. LIII, #1777. [5] Nishiizumi K. etal. (2022) Hayabusa Symposium 2022. S21-08. [6] Okazaki R. et al. (2022) Science. 379, eabo0431. [7] Nishiizumi K. et al.
(1985) Lunar Planet. Sci. XVI, 620-621. [8] Nagao K. et al. (2023) Hayabusa Symposium 2023 (this meeting). [9] Sharma P. etal. (2000) Nucl. Instrum. Methods Phys. Res. B 172, 112-123. [10] Nishiizumi K. (2004) Nucl. Instrum. Methods Phys. Res.
B223-224, 388-392. [11] Nishiizumi K. et al. (2007) Nucl. Instrum. Methods Phys. Res. B258, 403-413. [12] Yokoyama T. etal. (2022) Science. 379, eabn7850. [13] Masarik J. and Reedy R. C. (1994) Geochim. Cosmochim. Acta. 58, 5307-5317.

Noble Gases of the 1st and 2nd AO Ryugu Samples Collected by the Hayabusa2 Spacecraft
Keisuke Nagao1*, Kunihiko Nishiizumi2, Marc W. Caffee3, Hwayoung Kim1, Changkun Park1, Jong Ik Lee1, Jozef Masarik4
KOPRI, Incheon 21990, Korea, 2Space Sciences Laboratory, Univ. of California, Berkeley, CA 94720-7450, USA.,3Dept. ofPhysics & Astronomy, Purdue Univ., West Lafayette, IN 47907-2036, USA, 4Comenius Univ., Bratislava, Slovakia, *present
address: Seki 2082, Maniwa-shi, Okayama 719-3156, Japan. knagao520@gmail.com
1

Hayabusa2 arrived at the C-type asteroid 162173 Ryugu in June 2018, and successfully collected surface samples fromtwo sampling sites, returning ~5.4 g of samples to Earth on December 6, 2020. Surface samples stored in Chamber A werecollected during the 1st touchdown (TD) on Ryugu’s surface on February 21, 2019. A crater (diameter of ~14 m) on Ryugu’s
surface was made using a collision device - denoted “Small Carry-on Impactor (SCI)” on April 5, 2019 [1]. Samples in Chamber
C were collected proximal to this artificial crater and are possibly ejecta from the north side of the crater by the 2nd TD on July11, 2019 [2].
Our studies on the Hayabusa2 samples are based on the measurement of those nuclides produced in asteroidal surface
materials by both solar (SCR) and galactic cosmic rays (GCR). Cosmic-ray-produced (cosmogenic) nuclides are used todetermine the duration and nature of the exposure of materials to energetic particles [3]. Our goals are to understand both thefundamental processes on the asteroidal surface and the evolutionary history of its surface materials. These processes occur overtimescales spanning the present to 109 yrs into the past, and are important not only for understanding the history of Ryugu’s
surface but also for studies of asteroid-meteoroid evolutionary dynamics. For Hayabusa2 samples, there are several specificquestions we aim to address: (1) are the Chamber C samples, collected during the 2nd TD, ejecta deposits from the artificial
crater, (2) if so, what is the original depth of each recovered sample grain in the Ryugu regolith, and (3) what is the averagesurface exposure time, mixing rate of regolith materials, and erosion/escape rate of Ryugu’s surface? We investigate and utilize
cosmogenic radionuclides (10Be, 26Al, 36Cl, and 41Ca) and noble gases, especially cosmogenic 21Ne in Ryugu samples. Expected
maximum cosmogenic nuclide concentrations in millimeter-sized (~1 mg in mass) Ryugu sample are a few times 105 - 107 atoms
or lower. These values are higher than the present detection limits of accelerator mass spectrometry (AMS) and noble gas mass
spectrometry, but 2 orders of magnitude smaller than normal studies of cosmogenic nuclide measurements in meteoritic materials.
We present here the noble gas isotopic compositions of 6 samples (Table 1) allocated as the 1st and 2nd AO. Noble gases
were measured with the system of modified-VG5400 mass spectrometer at Korea Polar Research Institute (KOPRI). The noble
gas system had been used to measure the Itokawa samples at the University of Tokyo [4], and then moved to KOPRI afterward
in 2015. Noble gases were extracted from each sample using a miniature furnace specially designed for small samples, using a
Ta-tube with a Mo-crucible. A sample dropped into the crucible is heated from outside of the Ta-tube by a W-heater. Electric
current applied to the W-heater is controlled by a computer program monitoring the heating temperature with a W-Re
thermocouple. Samples were installed in a glass-made sample holder, which was set on the furnace and preheated for a day at
about 120°C to remove atmospheric noble gas contamination adsorbed on the samples. Stepwise heating was applied to extract
noble gases, i.e., 200, 900, and 1700°C for small samples (A0130, C0162, and C0182), and 200, 600, 900, 1200, and 1700°C forlarger samples (A0221, C0012, and C0212). The extracted noble gases from each sample were purified and separated into 5
fractions, i.e., He, Ne, Ar, Kr, and Xe, then measured isotope abundances and isotopic ratios for each fraction.
Total values of concentrations of 4He, 20Ne, 36Ar, 84Kr, and 132Xe, and isotope ratios of He, Ne, and Ar obtained by the
stepwise heating method are presented in Table 1. Data of Orgueil CI chondrite measured in this work are also presented forcomparison. Solar He and Ne with very high concentrations of 4He (14.9 and 9.3×10-4 cm3STP/g) and 20Ne (2.0 and 1.5×10-3
cm3STP/g) were observed for the aggregate samples A0221 and C0212, respectively. These samples showed 20Ne/22Ne ratios of
12.8–13.7 in the temperature range of 200–900°C. The ratios are close to the value of 13.78 for solar wind (SW) [5]. Releasepeaks of 4He for these samples were at the heating temperature of 600°C, for which 3He/4He was 3.9×10-4, slightly lower thanthe SW value of 4.64×10-4 [5]. Smaller amounts of SW He and Ne are also indicated in A0130. Neon isotopic compositions forother samples are a mixture of several primitive components, e.g., P1 (Ne-Q), P3 (presolar diamond), and Ne-E(H) (SiC) [6].
Xe isotopic ratios, e.g., 130Xe/132Xe, 129Xe/132Xe, and 136Xe/132Xe, indicate that trapped Xe is mostly Q-Xe component, with asmall or negligible contribution of cosmogenic and HL or fissiogenic Xe.
Concentrations of cosmogenic 3He were difficult to calculate, because only a small excess of cosmogenic 3He wasobserved at the low heating temperatures at 200–900℃ for some samples (3He/4He = 5.2, 7.3, 4.9, and 4.8×10 -4 for A0221,
C0012, C0162, and C0212, respectively), and most 3He/4He ratios were between 1.23×10-4 for trapped Q-He [6] and 4.64×10-4
for SW [5]. Neon isotopic compositions are a mixture of several primitive components, e.g., SW [5], P1 (Ne-Q), P3 (presolar
diamond), and Ne-E(H) (SiC) [6], to which a small contribution of cosmogenic 21Ne was detected. Calculated concentrations ofcosmogenic 21Ne in excess of the assumed trapped 21Ne/22Ne = 0.029 are presented in Table 1. The concentrations of cosmogenic
21
Ne are (4.06–11.9)×10-9 cm3STP/g. The concentrations of 11.9 and 9.83×10-9 cm3STP/g for aggregate samples A0221 andC0212, respectively, are higher than those observed for the initial analysis samples, (1.6–7.8)×10-9 cm3STP/g [7, 8]. Exposure
depths were estimated from preliminary measurements of 10Be and/or 26Al in same samples. Then, each production rate P21 was
obtained by new calculation using the MCNP Code System. Calculated cosmic ray exposure (CRE) ages are shown in Table 1.
CRE ages calculated for the samples from Chamber-A are roughly 4 and 11 Myr for A0130 and A0221, respectively. CRE agesfor 3 samples from Camber-C, C0012, C0162, and C0182, are in the range of 3–5 Myr, while C0212 has longer CRE age of 89 Myr. The CRE ages of 3–5 Myr for the samples from Chamber-A and -C are similar to the reported ages for initial analysis
samples, 3–5 Myr [7] and 5 Myr [8]. Contrary to these grain samples, two aggregate samples A0221 and C0212 with longer
CRE ages are enriched in SW-Ne. Samples measured in the present work must have been irradiated heterogeneously by both
GCR and SW on the Ryugu’s surface before sampling by the Hayabusa2.
Table 1. Concentrations and isotopic ratios of noble gases 1) in 6 Ryugu samples and Orgueil CI chondrite.
4
20
36
84
3
21
Stepwise
Sample
Mass
He
Ne
Ar
Kr 132Xe
He/4He 20Ne/22Ne 21Ne/22Ne 38Ar/36Ar 40Ar/36Ar
NecosmP 213)
mg
heating2)
10-9cm3STP/g
10-4
10-9 cm3 STP/g 10-9 cm3 STP/g/Myr
A0130
0.2086
3 steps
219000
1230
1600
15.9
19.3
3.84
10.54
0.06540.1858
1.79
4.41
1.10-1.20
A0221
1.66105 steps 1490000
20400
3430
16.9
18.5
3.54
12.85
0.03620.1842
0.485
11.9
1.20
C0012
2.21795 steps
97700
472
1530
15.9
19.6
3.59
8.27
0.09780.1861
0.419
4.06
1.12–1.20
C0162
0.1886
3 steps
118000
706
1430
15.3
17.7
4.46
8.68
0.09840.1867
1.34
5.83
1.13–1.17
C0182
0.27683 steps
93800
432
1370
20.5
17.0
3.80
8.09
0.12800.1876
1.18
5.45
1.15–1.20
C0212
0.82325 steps
932000
15200
2720
16.1
18.7
3.89
12.95
0.03710.18490.427
9.83
1.12–1.17
Orgueil(CI) 1.7205
3 steps672000
1130
1260
13.0
15.7
3.51
10.08
0.10990.18562.37
9.37
2.224)
1)
Isotopic ratios of Kr and Xe are not presented.
2)
Heating temperatures are 200, 900, and 1700°C for 3 steps, and 200, 600, 900, 1200, and 1700°C for 5 steps.
3)
Each depth was estimated based on prelininary measurements of cosmogenic radionuclides. The production rates and CRE ages were not included ±5 % uncertainty of our new
calculations and experimental errors.
4)

Prodction rate in 4π-geometry for CI chondrites [9].

Acknowledgment: We thank Hayabusa2 project team, especially the curation members. We also thank HMNH-Paris forproviding Orgueil sample.
References[1] Arakawa M. et al. 2020. Science 368, 67–71[2] Tsuda Y. et al. 2020. Acta Astronautica 171, 42–54[3] Reedy R. C. et al. 1983. Annu. Rev. Nucl. Part. Sci. 33, 505–537.
[4] Nagao K. et al. 2011. Science 26, 1128–1131.
[5] Heber V. S. et al. 2009 Geochim. Cosmochim. Acta 73, 7414–7432.
[6] Ott U. (2002) Noble gases in Geochem. and Cosmochem., Rev. in Mineral. Geochem. 47, 71–100.
[7] Nagao K. et al. 2022. Meteoritical Soc. Meeting, Abstract #6134.
[8] Okazaki R. et al. 2023. Science 379, 788.
[9] Eugster O. 1988. Earth Planet Sci. Lett. 52, 1649–1662.

T21 3)
Myr
3.7–4.0
9.9
3.4-3.6
5.0–5.2
4.5–4.7
8.4–8.8
4.22

Insights into Early Solar System Isotopic Reservoirs Inferred from Ryugu
Quinn R. Shollenberger1, Jan Render1, and Gregory A. Brennecka1
1
Lawrence Livermore National Laboratory
Introduction: Returned primitive Solar System material presents a unique opportunity to address multiple important
planetary science questions. Recent work has demonstrated that material returned from the Japan Aerospace Exploration
Agency’s (JAXA) Hayabusa2 mission from Cb-type asteroid (162173) Ryugu is most closely related to Ivuna-type (CI)
carbonaceous chondrites [e.g., 1-2], which have a chemical composition similar to that of the Sun’s photosphere. The pristinenature and CI-like chemical composition of Ryugu samples allows researchers to use bulk-rock nucleosynthetic isotope
anomalies to establish genetic relationships to planetary bodies and to refine our knowledge of the isotopic evolution of the
Solar System, as well as the accretion history of the terrestrial planets [e.g., 1-6].
The initial isotopic study of four Ryugu particles found it has an indistinguishable Fe isotope composition from CI
chondrites—which is itself different from all other carbonaceous chondrites [2]. This led to the conclusion that a third isotopic
reservoir may have existed in the early Solar System for CI and CI-like bodies to form separate from the carbonaceous andnon-carbonaceous reservoirs. However, the existence of a third isotopic reservoir has recently been challenged through two
different models [7-8], and those studies have shown that the isotopic dichotomy between carbonaceous and non-carbonaceous
meteorites extends to Fe isotopes. These authors suggest that the appearance of an apparent third isotopic reservoir in themeteorite record reflects a lack of Fe isotope data from carbonaceous achondrites [8]. Here we report Fe and Ti isotopic
analyses with the addition of Ni isotope compositions on a bulk sample from Ryugu to shed new light on the isotopic
reservoirs present in the early Solar System.
Methods: Ryugu particle A0208, provided by JAXA, was analyzed in this study. This particle was part of a surface sample
that was collected in Chamber A during the first touchdown of the Hayabusa2 spacecraft. Approximately 8 mg of Ryugu
particle A0208 was weighed and dissolved in a pre-cleaned PFA vial using a combination of concentrated HF:HNO3, followedby aqua regia. Two procedural blanks as well as the geostandards BCR-2 and BHVO-2 were processed alongside our Ryugu
sample for all procedures. Following dissolution, we obtained major and trace element concentrations using a Thermo
Scientific Element XR ICP-MS at Lawrence Livermore National Laboratory (LLNL) following previously published methods[9].
All samples were processed through multiple chemical separations to purify the elements of interest using previously
established procedures. The first separation was to isolate Fe from the sample matrix [10] followed by purification of Ti [e.g.,
11] and Ni [e.g., 12]. Yields of our procedures were >80% and the blanks were negligible considering the total amount ofmaterial processed for Fe, Ti, and Ni. Iron and Ni isotopic analyses were performed on a Thermo Scientific Neptune Plus MCICPMS at LLNL while Ti isotopes were measured on a Thermo Scientific Neoma MC-ICPMS at LLNL [e.g., 2, 11-12].
Results and Discussion: Whereas the previously analyzed Ryugu particles were all around 25 mg or less [1-2], our particle
A0208 weighed only 8 mg. Despite this difference and the limited masses in general, we observe that our Ryugu particle
exhibits elemental concentrations comparable to what has been reported in previous work (Fig. 1). Shown in figure 1 are major
and trace element concentrations obtained for particle A0208 against the average concentration data from the initial Ryugu
study [1], demonstrating overall excellent agreement. A few
small differences exist between the two works (the mostnotable being Be), which are readily explained byheterogeneities at these small sample scales (< 25 mg).
Figure 1. Major and trace element abundances of Ryugu A0208
particle of this work plotted against the average concentrations
determined for Ryugu particles A0106, A0107, and C0108 from[1]. With a few exceptions, most elements are in good agreement
between the two studies. Uncertainties for ICP-MS data from thisstudy are estimated to be ±5%, whereas error bars shown for datafrom [1] are two standard deviations of the two ICP-MS
measurements reported in that work.

Shown in Figure 2 are select Ti, Fe, and Ni isotope data commonly used for genetic comparison of meteoritic materials.
Our measured Fe and Ti isotopic compositions are indistinguishable from other Ryugu particles as well as from CI chondrites[1-2]. The overlapping Fe and Ti isotopic compositions of our Ryugu particle with previous measurements indicate that sample
heterogeneity is not a big concern for major elements analyzed here. Although specific values and uncertainties were notprovided in [13], our Ni isotope data from Ryugu particle A0208 appear to be consistent with these previous Ni isotope
measurements as well as CI chondrites (Fig. 2). This result offers further support to the interpretation that Ryugu is mostclosely related to CI chondrites [1-2, 13].
The new Ti, Fe, and Ni isotopic data obtained in this study demonstrate that Ryugu and CI chondrites may plot on acontinuation of a trend defined by the carbonaceous chondrites. Previous studies have suggested that CI chondrites and Ryugu
may have formed at greater heliocentric distances compared to other carbonaceous chondrites [e.g., 2, 13-14] and our data aresupportive of this interpretation given that Ryugu and CI chondrites are an endmember in the carbonaceous reservoir. While
our data do not clearly provide evidence for the existence of a third isotopic reservoir in the early Solar System as previously
suggested [2], this is not ruled out, either. Additional isotopic measurements are underway at LLNL for Cr and any finalized
data and further interpretations will be reported at the meeting.

Figure 2. Plots of µ54Fe vs. µ50Ti, µ62Ni vs. µ50Ti, and µ54Fe vs. µ62Ni, where µ designates parts per million deviation from a terrestrial
standard. Ryugu particle A0208 from this study is the large light blue diamond, previous Ryugu measurements are shown as a light blue
triangle, average CI chondrite as a light blue circle, carbonaceous chondrites (CC) as dark blue circles, non-carbonaceous meteorites (NC) in
red circles, and Earth as a green square. Iron and Ti isotopic data from [2]. Ni isotopic data compiled from [15-19].

Acknowledgements: The authors thank JAXA for providing Ryugu particle A0208 that was used in this study. This work
was performed under the auspices of the U.S. DOE by LLNL with contract DE-AC52-07NA27344 with release number
LLNL-ABS-848622. This work was funded by the Laboratory Directed Research and Development program of Lawrence
Livermore National Laboratory (23-LW-015).
References[1] Yokoyama T. et al. (2022) Science 10.1126/science.abn7850. [2] Hopp T. et al. (2022) Science Advances 8, eadd8141. [3]Fischer-Gödde M. & Kleine T. (2017) Nature 541, 525-527. [4] Burkhardt C. (2021) Science advances 7, eabj7601. [5]Schiller M. et al. (2020) Science Advances 6, eaay7604. [6] Burkhardt C. et al. (2019) Geochimica et Cosmochimica Acta 261,
145-170. [7] Marrocchi Y. et al. (2023) The Astrophysical Journal Letters 954, L27. [8] Yap T. & Tissot F.L.H. (2023) Icarus
405, 115680. [9] Wimpenny J. et al. (2022) Earth & Planetary Science Letters 578, 117318. [10] Rolison J. M. et al. (2019)
Applied Geochemistry 103, 97-105. [11] Shollenberger Q. R. et al. (2022) Geochimica et Cosmochimica Acta 324, 44-65. [12]Render J. et al. (2018) The Astrophysical Journal 862, 26. [13] Spitzer F. et al. (2023) LPSC #2488. [14] Desch S.J. (2018)
The Astrophysical Journal 238, 11. [15] Steele R.C.J. et al. (2012) The Astrophysical Journal 758,59. [16] Tang H. & Dauphas
N. (2012) Earth & Planetary Science Letters 359-360, 248-263. [17] Tang H. & Dauphas N. (2014) Earth & Planetary Science
Letters 390, 264-274. [18] Regelous M. et al. (2008) Earth & Planetary Science Letters 272, 330-338. [19] Burkhardt C. et al.
(2017) Meteoritics & Planetary Science 52, 807-826.

Nickel isotopic composition of Ryugu and the link between CI and other carbonaceous chondrites
T. Kleine F. Spitzer1, C. Burkhardt1, the Hayabusa2-initial-analysis chemistry team, and the Hayabusa2-initial-analysis core1
Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
The initial analyses of samples returned from Cb-type asteroid 162173 Ryugu by JAXA’s Hayabusa2 mission provided
isotopic, mineralogical, and chemical evidence for a close link of Ryugu to CI chondrites [1,2]. A subsequent study has shownthat Ryugu and CI chondrites share the same nucleosynthetic Fe isotope signatures, which are distinct from those of othercarbonaceous chondrites [6]. This not only demonstrates that Ryugu and CI chondrites are genetically linked, but also that they
derive from another reservoir than all other carbonaceous chondrites [3]. However, the origin of these distinct Fe isotopic
compositions of CI chondrites/Ruygu compared to other carbonaceous chondrites is not well understood. Nickel isotopes holdconsiderable promise to further investigate the genetic link between Ryugu and CI chondrites. When normalized to 61Ni/58Ni,
CI chondrites do not only display the largest µ62Ni and µ64Ni anomalies among carbonaceous chondrites (where µiNi is theparts-per-million deviation from terrestrial standard values), but they also have a distinct µ60Ni composition compared to allother known carbonaceous chondrite-like materials. We obtained four Ryugu samples (A0106–A0107, A0106, C0108, C0107)
along with six carbonaceous chondrites including the CI chondrites Orgueil and Alais, which have been chemically processedalongside the Ryugu samples [2]. In addition, we also measured several grouped and ungrouped carbonaceous chondrites.
Chemical purification of Ni involved a 3-step ion-exchange chromatographic procedure that achieves sufficiently low 58Fe/58Ni
and 64Zn/64Ni ratios in the final purified Ni cuts to allows for accurate and precise correction of isobaric interferences. All
isotope measurements were performed on the Thermo Scientific NeptunePlus MC-ICP-MS at the Institut für Planetologie,
University of Münster. Instrumental mass bias is corrected by internal normalization to either 61Ni/58Ni or 62Ni/61Ni using the
exponential law. All data are reported in the µ-notation as the parts per 106 deviation relative to the standard.
The new Ni isotopic data for CM, CO, CV, and CR chondrites agree
well with those reported in previous studies and reveal that thesechondrites are characterized by negative µ60Ni and positive µ62Ni andµ64Ni values (Fig. 1). The two ungrouped carbonaceous chondrites
Tagish Lake (TL) and Tarda, for which no Ni isotopic data have beenreported previously, have Ni isotope anomalies similar to thosecarbonaceous chondrites. By contrast, CI chondrites display distinct
Ni isotopic compositions and particular distinctly larger µ64Ni andµ60Ni compared to other carbonaceous chondrites (Fig. 1).
Importantly, the Ni isotopic compositions of all four Ryugu samples
overlaps with those of the CI chondrites, indicating distinct Ni
isotopic compositions of CI chondrites/ Ryugu compared to all othercarbonaceous chondrites (Fig. 1). This is consistent with theFig. 1: µ60Ni versus µ64Ni for non-carbonaceous (NC) andnucleosynthetic Fe isotope variations among carbonaceous chondrites, carbonaceous (CC) meteorites. CI chondrites and Ryugu
which also reveal a uniquely distinct composition for CI chondrites have distinct Ni isotopic compositions compared to NC andCC meteorites.
and Ryugu [3].
Isotopic variations among carbonaceous chondrites are thought to reflect variable proportions of three main components
having distinct isotopic compositions: refractory inclusions (e.g., CAI), chondrules/chondrule precursors, and CI chondrite-like
matrix [4, 5]. The incorporation of CI chondrite-like matrix in other groups of carbonaceous chondrites is consistent withsystematic variations of (i) volatile element contents, (ii) mass-dependent isotope fractionations of moderately volatileelements, and (iii) nucleosynthetic 54Cr anomalies with the fraction of matrix in each chondrite. However, in Ni isotope space,
CI chondrites (and Ryugu) are offset from the composition of other carbonaceous chondrites, indicating that CI chondrites are
not fully representative of the matrix in other groups of carbonaceous chondrites. Instead, this matrix appears to have formed
from different precursor material than CI chondrites, either because it formed in a different area of the disk or because it was
modified by processes in the disk prior to its incorporation in carbonaceous chondrites.
References[1] Yada T. et al. 2022. Nature Astronomy 6:214–220. [2] Yokoyama T. et al. 2022. Science abn7850. [3] Hopp T. et al. 2022.
Science Advances 8:8141. [4] Alexander 2019. Geochimica et Cosmochimica Acta 254:277-309. [5] Hellmann et al. 2023.
Astrophysical Journal Letters 946: L34.

The magnesium isotope composition of samples returned from asteroid Ryugu

1

Martin Bizzarro1,2*, Martin Schiller1, Tetsuya Yokoyama3 and the Hayabusa2 Initial Analysis Team
Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, K 1350, Denmark.*email:bizzarro@sund.ku.dk
2
Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, 75005 Paris, France
3
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551, Japan.

The nucleosynthetic isotope composition of planetary materials provides a record of the heterogeneous distribution of stardust
within the early Solar System. Thus, nucleosynthetic signatures can be used to infer genetic relationships between early formed
bodies and, ultimately, provide constraints on their accretion regions. In December 2020, the Japan Aerospace Exploration
Agency Hayabusa2 spacecraft returned to Earth the first samples of a primitive asteroids, namely the Cb-type asteroid Ryugu.
This provides a unique opportunity to explore the kindship between primitive asteroids and carbonaceous chondrites. Based on
chemistry, mineralogy, petrology and isotope systematics of various elements, it has been proposed that Ryugu samples areclosely related to Ivuna-type (CI) carbonaceous chondrites. Indeed, the bulk nucleosynthetic isotope compositing for tracers
like 54Cr and 50Ti as well as the chemical abundances of most elements are within the range of CI chondrites. Moreover, like
CIs, Ryugu samples experienced extensive aqueous alteration in the presence of water and mainly consist of hydrous silicates(serpentine and saponite) and other secondary minerals (i.e., carbonate, magnetite, and sulfide) interpreted to have formed
during asteroidal fluid circulation.
High-precision Mg isotope measurements can provide a novel perspective on the kinship between Ryugu with CI chondrites
and, by extension, the accretion region of Cb-type asteroids. Magnesium isotope variability in Solar System materials canoriginate from the decay of the short-lived 26Al nuclide as well as primary nucleosynthetic processes. Moreover, Mg isotopes
can also be fractionated according to their masses by high-temperature events in the protoplanetary disk or, alternatively, by
low-temperature parent body secondary. Thus, the combination of high-precision mass-independent and mass-dependent Mg
isotope compositions is useful to understand genetic relationships and accretion history of planetary materials.
Here, we report high-precision µ26Mg* and µ25Mg values of Ryugu samples together with those of CI, CM, CV and ungroupedcarbonaceous chondrites. The stable Mg isotope composition of Ryugu aliquots define µ25Mg values ranging from –160±20
ppm to –272±30 ppm, which extends to lighter compositions relative to Ivuna-type (CI) and other carbonaceous chondrite
groups. We interpret the µ25Mg variability as reflecting heterogenous sampling of a carbonate phase hosting isotopically light
Mg (µ25Mg ~–1400 ppm) formed by low temperature equilibrium processes. After correction for this effect, Ryugu samples
return homogenous µ26Mg* values corresponding to a weighted mean of 7.1±0.8 ppm. Thus, Ryugu defines a µ26Mg* excess
relative to the CI and CR chondrite reservoirs corresponding to 3.8±1.1 and 11.9±0.8 ppm, respectively. These variations
cannot be accounted for by in situ decay of 26Al given their respective 27Al/24Mg ratios. Instead, it requires that Ryugu and the
CI and CR parent bodies formed from material with a different initial 26Al/27Al ratio or that they are sourced from material
with distinct Mg isotope compositions. Thus, our new Mg isotope data challenge the notion that Ryugu and CI chondrites
share a common nucleosynthetic heritage.

Oxygen isotope systematics of crystalline silicates in comet Wild 2: Comparison to anhydrous
minerals in Ryugu and CI chondrites
Noriko T. Kita1, Mingming Zhang1, Donald E. Brownlee2 and David J. Joswiak2
1
WiscSIMS, Department of Geoscience, University of Wisconsin-Madison2
Department of Astronomy, University of Washington
Initial analyses of Ryugu returned samples indicated that they are similar to CI (Ivuna-type) carbonaceous chondrites,
which mainly consist of minerals that formed by parent body aqueous alteration [e.g., 1-5]. Discovery of CO2 bearing fluidinclusions in Ryugu pyrrhotite suggests that the Ryugu parent body accreted in the outer solar system beyond the CO2 and H2Osnowlines (>3-4 au [2]). Kawasaki et al. [6] conducted oxygen isotope analyses of anhydrous minerals, such as olivine andpyroxene that are extremely rare in Ryugu and CI chondrite Ivuna. They examined the distribution of mass-independent
fractionation factors of oxygen 3-isotopes, expressed by ∆17O (= δ17O – 0.52 × δ18O), in olivine grains from Ryugu and CI
chondrites, and found them to be similar to those of comet Wild 2 from the NASA Stardust mission [7-12]. They suggested thatthe formation region of the Ryugu asteroid could have been farther into the outer solar system than most carbonaceous chondrites
and closer to the accretion region of comets.
Here, we summarize oxygen isotope data of olivine and pyroxene from comet Wild 2. To date, ~90 relatively coarsegrained particles (>2 µm to upto 60 µm) have been analyzed for oxygen isotopes, including ~20 from the literature [7, 9-13] and~70 from recent studies [14-16]. These latter studies include more than 50 particles extracted from the longest type B Stardust
track (~17 mm) T227, which contains numerous relatively coarse (>2 µm up to 20 µm) particles in the bulb region in addition
to at least four terminal particles (TP). The largest TP measures 60 µm in diameter and has a porphyritic chondrule-like texture[16]. The majority of Wild 2 particle analyses were conducted at the WiscSIMS IMS 1280 using a 2 µm-sized primary beam [7,9, 12-16]. Oxygen isotope data of individual olivine and pyroxene particles are shown in the plot of ∆17O versus Mg# (molar[Mg]/[Mg+Fe] in Figure 1. This diagram has been used for the studies of meteoritic chondrules to understand the isotope
signatures of precursors and redox states during their formation [e.g., 17]. We also summarize published oxygen isotope analysesof olivine and pyroxene from Ryugu [6, 18] and other CI chondrites [6, 19-20] for comparison (Figure 2).
Wild 2 olivine and pyroxene show a wide range of Mg# ranging from 100 to 50 and are evenly distributed (Figure 1).
The ∆17O values are bimodal where most particles are 16O-poor with ∆17O values ranging from –7‰ to +7‰ and others with
∆17O of ~ –22‰, values similar to CAIs in carbonaceous chondrites. The latter 16O-rich particles are either LIME (low iron and
Mn-enriched) olivine, nearly pure forsterite, or enstatite, all which are with highest Mg#≥98. They are likely early solar nebula
condensates similar to those in AOAs [9,12]. In addition, rare occurrences of 16O-rich relict olivine have been identified, suchas in the chondrule-like object Gozen-sama, studied by [7]. The 16O-poor particles show a general tendency of a slight increasein ∆17O values with decreasing Mg# (Figure. 1). The majority of Wild 2 particles (60-70%) are FeO-rich (Mg#<90) and manyof them show zero to slightly positive ∆17O values. Similar results have been obtained from Giant Cluster IDP U2-20GCA [21],which is considered to be of cometary origin [22]. They overlap with data from CR chondrite chondrules [16, 23-25], suggestinga genetic relationship between CR chondrites and cometary particles [e.g., 9], though FeO-rich chondrules are uncommon in CR
chondrites and do not show ∆17O values higher than 1‰ [12, 16, 21].
Olivine and pyroxene data from Ryugu and CI chondrites are summarized in Figure 2. Most grains have high Mg#(≥98) with bimodal ∆17O values of ~–5‰ and –22‰ and minor FeO-rich grains show ∆17O values of ≤0‰. Similar to Wild 2
particles, 16O-rich olivine grains are often Mn-rich [6, 18, 20] and may be related to AOAs (e.g., [26]). However, the majorityof 16O-poor olivine and pyroxene in Ryugu and CI chondrites cluster at the ∆17O values of –5‰, which are uncommon among
Wild 2 particles. Ryugu and CI data are more similar to chondrule data in major carbonaceous chondrites, such as CMs and CVs(e.g., [27-28]). Rare chondrule-like objects were identified in Ryugu [29], though they are substantially smaller than typicalchondrules in carbonaceous chondrites.
Several Wild 2 particles are chondrule-like objects containing plagioclase and glass [7, 9-11, 16, 30]. Two of them werestudied for 26Al-26Mg chronology, but do not show any resolvable excess 26Mg [9, 31], suggesting that they formed later than 34 Ma after CAI formation (by assuming homogeneity of 26Al in the solar system). In contrast, the Ryugu and CI chondrite parent
bodies might have accreted much earlier ~2 Ma after CAIs and experienced aqueous alteration by the heat generated from 26Al
decay [2]. Thus, a major difference between anhydrous minerals in comets and CI chondrites could be related to the timing ofaccretion in the outer solar system. Comet Wild 2 contains late-forming (>3 Ma) chondrule-like materials, which may haveformed in the outer solar system [16]. They were not present in the Ryugu and CI chondrite-forming regions at the time of the
CI chondrite parent body accretion.

Figure 1. Mg# vs. Δ17O relationship among olivine and pyroxene particles in comet Wild 2 (after Zhang et al. [16]). Data sources: Literature[7, 9-13], T227 [16] and others [14-15]. Data from CR chondrules [17, 23-25] are plotted for comparison (error bars are ignored). Chondrulelike objects are shown as circles [7, 9, 11, 16] including 16O-rich relict olivine data [7, 16].

Figure 2. Mg# vs. Δ17O relationship among olivine and pyroxene grains in Ryugu (K23 [6]; L22 [18]) and CI chondrites Orgueil (P20 [19]),
Ivuna (K23, M22 [20]), and Alais (M22). The Wild 2 comet data (Figure 1) and CM and CV chondrite chondrule data [27-28] are shown forcomparison (error bars are ignored). Majority of 16O-poor Ryugu and CI chondrite data show systematically lower ∆17O and higher Mg# thanthose of Wild 2.

References [1] Yokoyama T. et al. 2023. Science 379:eabn7850. [2] Nakamura T. et al. 2023. Science 379:eabn8671. [3] Ito M.
et al. 2022. Nat. Astron. 6:1163–1171. [4] Nakamura E. et al. 2022. Proc. Jpn. Acad., Ser. B 98:227–282. [5] Yamaguchi A. et
al. 2022. Nat. Astron. 7:398–405. [6] Kawasaki N. et al. 2022. Sci. Adv. 8:eade2067. [7] Nakamura T. et al. 2008. Science
321:1664–1667. [8] Nakamura-Messenger K. et al. 2011. MaPS 46:1033–1051. [9] Nakashima D. et al. 2012. EPSL 357–
358:355–365. [10] Ogliore R. C. et al. 2012. ApJ. L745:L19. [11] Ogliore R. C. et al. 2015. GCA 166:74–91. [12] Defouilloy
C. et al. 2017. EPSL 465:145–154. [13] Joswiak D. J. et al. 2014. GCA 144:277-298. [14] Chaumard N. et al. 2018. Abstract#2163. 49th LPSC. [15] Zhang M. et al. 2022. Abstract #1057. 53rd LPSC. [16] Zhang M. et al. 2023. Abstract #. 1711. 54th
LPSC. [17] Tenner T. J. et al. 2015. GCA148:228-250. [18] Liu M. et al. 2022. Nat. Astron. 6: 1172–1177. [19] Piralla M. et al.
2020. GCA 269: 451-465. [20] Morin G. L. F. et a. 2022. GCA 332: 203-219. [21] Zhang M. et al. 2021. EPSL 564:116928.
[22] Joswiak D. J. et al. 2017. MaPS 52:1612-1648. [23] Connolly H. C. and Huss G. R. 2010. GCA 74:2473–2483. [24] Schrader
D. L. 2013. GCA 101:302-327. [25] Schrader D. L. 2014. GCA 132:50-74. [26] Mikouchi T. et al. 2022. Abstract #. 1935. 53rd
LPSC. [27] Chaumard M. et al. 2018.GCA 228: 220-242. [28] Hertwig A. T. et al. 2018. GCA 224:116-131. [29] Nakashima D.
et al. 2023. Nat. Commun. 14:532. [30] Joswiak D. J. et al. 2012. MaPS 47:471-524. [31] Nakashima D. et al. 2015. EPSL
410:54-61.

Oxygen isotopic composition of dolomite in Ryugu: New insights into the thermal history of the
Ryugu parent body.
Wataru Fujiya1, Takayuki Ushikubo2, Shingo Sugawara1, Akira Yamaguchi3, Kohei Fukuda4, Martin R. Lee5, Kentaro Terada4,
Phillip A. Bland6 and Bryan J. Travis7
1
Faculty of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, JAPAN (wataru.fujiya.sci@vc.ibaraki.ac.jp),2
Kochi Institute for Core Sample Research, JAMSTEC, 3National Institute for Polar Research, 4Osaka University, 5Glasgow
University, 6Space Science and Technology Centre, Curtin University, 7Planetary Science Institute
Introduction: Ryugu samples underwent extensive aqueous alteration, and a variety of secondary minerals such as
phyllosilicate, oxide, sulfide, and carbonate formed during water-rock interaction [1-5]. Among the secondary minerals,
carbonates are of particular interest because their O and C isotopic compositions reflect the conditions of aqueous alteration,and because they can be dated using the 53Mn-53Cr systematics. Previous studies of the O and C isotopic compositions of
dolomite (CaMg(CO3)2) in Ryugu have suggested that it formed at temperatures lower than 80 °C [1,2,6,8] when the system
was approaching equilibrium [7,8]. The 53Mn-53Cr dating of Ryugu carbonate suggests that their formation may have spanned
as much as 5 Myr [1,6]. Therefore, Ryugu carbonate potentially helps us decipher the thermal history of the Ryugu parent
body. However, it is unclear whether Ryugu carbonate formed during prograde alteration when temperature was increasing or
during retrograde cooling, which makes it difficult to establish a realistic thermal history model. In this work, we investigatedthe O isotopic compositions of dolomite in Ryugu samples A0203 and C0192 to further constrain its formation conditions.
Also, we will measure the O isotopic compositions of magnetite in these samples to estimate the O isotopic equilibrium
temperatures between dolomite and magnetite.
Experimental: Prior to isotope work, the microstructures of dolomite grains in samples A0203 and C0192 were characterizedby Transmission Electron Microscopy (TEM) using a FEI T20 operated at 200 kV. The in-situ O-isotope analyses on two andsix dolomite grains from A0203 and C0192, respectively, were performed using CAMECA IMS 1280-HR [9]. Negative ionsof 16O−, 17O−, and 18O−, produced by a focused Cs+ primary ion beam (~30 pA, 3-4 µm in diameter), were simultaneously
detected with a Faraday cup (FC) for 16O− signals and two electron multipliers (EMs) for 17O− and 18O−. Instrumental massfractionation was corrected using a series of dolomite–ankerite standards [10]. The uncertainties on δ17O, δ18O, and Δ17O
values were typically ±1.12, ±0.86, and ±1.35‰ (2σ), respectively.
Results and discussion: TEM showed that dolomite grains in A0203 and C0192 differ in their crystal size and habit, withthose in A0203 typically being 1-2 m size euhedral crystals whereas C0192 dolomite is coarser and anhedral. The analyzed
dolomite grains have only a small variation in δ18O values as observed by previous studies [1,6-8]. The δ18O values of A0203
and C0192 dolomite are at the higher and lower end of those reported previously and clustered at 32.91 ± 0.47‰ (N = 6; 2SE)
and 26.54 ± 0.58‰ (N = 2; 2SE), respectively. Notably, the Δ17O values of A0203 and C0192 dolomite are also systematicallydifferent (−1.13 ± 0.82‰ and 0.46 ± 0.36; 2SE). A similar anti-correlation between δ18O and Δ17O values can also berecognized for the previous data, implying that Ryugu dolomite with higher δ18O values tends to have lower Δ17O values [6-8].
The Δ17O, and possibly, δ18O values of aqueous fluids are expected to have decreased during progressive aqueous alteration
because of the O-isotope exchange between water and anhydrous rock which initially had higher and lower Δ17O (and δ18O)
values [11,12]. Thus, the A0203 dolomite with lower Δ17O values likely precipitated from more evolved fluids that underwent
O-isotope exchange to a greater extent than the C0192 dolomite. On the other hand, the equilibrium O isotopic fractionation
between water and dolomite is larger at lower temperatures with the δ18O values of dolomite being higher than those of water[13]. Therefore, the A0203 dolomite with higher δ18O values likely precipitated at lower temperatures than the C0192 dolomite.
These observations may suggest that Ryugu dolomite formed during retrograde cooling. This argument is in line with the small
variation in δ13C values observed for Ryugu dolomite, which suggests its formation in higher O fugacity at the later stage of
aqueous alteration [7]. For further information regarding the formation conditions of dolomite, we plan to measure the 53Mn53
Cr ages of dolomite in A0203 and C0192.
References:[1] Yokoyama T. et al. 2022. Science 379: eabn7850. [2] Nakamura E. et al. 2022. Proc. Jpn. Acad., Ser. B 98: 227-282. [3] Ito
M. et al. 2022. Nat. Astron. 6: 1163-1171. [4] Nakamura T. et al. 2022. Science 379: eabn8671. [5] Yamaguchi A. et al. 2023.
Nat. Astron. 7: 398-405. [6] McCain K. A. et al. 2023. Nat. Astron. 7: 309-317. [7] Fujiya W. et al. 2023. Nat. Geosci. 16:
675-682. [8] Kita N. T. et al., submitted. [9] Fujiya W. et al. 2020. Geochim. Cosmochim. Acta 274: 246-260. [10] Śliwiński,M. G. et al. 2016. Geostand. Geoanal. Res. 40: 157-172. [11] Clayton & Mayeda 1984. Earth Planet. Sci. Lett. 67: 151-161.
[12] Marrocchi et al. 2018. Earth Planet. Sci. Lett. 482: 23-32. [13] Zheng Y.-F.et al. 1999. Geochem. J. 33: 109-126.

Numerical Simulation of Ryugu’s Thermophysical Properties using the Discrete
Element Method
B. Agrawal1 , M. Grott1 , J. Knollenberg1 , J. Biele2 , B. Gundlach3 , J. Blum4
1

German Aerospace Center, Berlin, Germany, 2 German Aerospace Center, Köln, Germany, 3 Westfälische
Wilhelms-Universität Münster, Germany, 4 Technische Universität Braunschweig, Germany

Between June 2018 and November 2019, the Hayabusa2 mission [1] investigated the near-Earth asteroid (162173)
Ryugu. The main objective of the mission was to study this pristine C-type asteroid to better understand the origin
and evolution of materials in the early solar system. Hayabusa2 deployed the MASCOT lander in October 2018 andfollowing a detailed remote sensing and in-situ investigation, Hayabusa2 returned samples to Earth in December 2020.
A summary of main findings of the mission was recently reviewed by [2], who also compared results obtained during
the remote sensing, in-situ, and sample analysis phases.
The detailed study of Ryugu over scales ranging from the micro (sample) scale to global remote sensing data revealed
that while several properties derived from remote sensing and in-situ analysis agree very well with results obtained fromthe sample analysis, some discrepancies exist [2]. These scale dependent effects include properties like reflectance andthermophysical properties. Here, we focus on the derived thermal properties, which were determined using MASCOT’s
MARA radiometer [3], the Hayabusa2 orbiter’s TIR thermal infrared imager [4], as well as the returned samples [5].
−2 −1 −1/2
While in-situ and remote sensing data roughly agree, yielding thermal inertias of 282+93
K s[6, 7] and−25 Jm−2 −1 −1/2
−2 −1 −1/2
225 ± 45 Jm K s[4, 8], respectively, sample analysis indicates values of 890 ± 45 Jm K s[5], which arethus about three times as large.
The reason for the observed scale dependence of the thermophysical properties remains unknown, but it has been
proposed that the difference could be caused by a thermal shielding effect on intermediate scales [5]. Cracks may,for example, be generated by thermal fatigue and a conceptual model of how these cracks may be distributed
insidepboulders is shown in the left panel of Fig. 1. Thermal fatigue would extend to a few skin depths dϵ = κP/π, whereκ = k/ρcp is thermal diffusivity, ρ is density, cp is specific heat, and P is the period of the forcing (a day-night cycle).
Remote sensing instruments like MARA and TIR are sensitive to material over a similar depth range, while samples
could contain considerably less cracks.

Figure 1: Left: Conceptual model of scale dependence of thermophysical properties. The range of materials sampled
by the in-situ and remote sensing instruments MARA and TIR is indicated in blue, while the returned samples areindicated in green. On large scales, the material may exhibit abundant cracks due to insolation induced fatigue, whilesamples may contain only few cracks. Middle: Modeling approach including cracks induced by thermal fatigue using
discrete elements. Fatigue induced cracks separating particles are indicated in blue. Right: First results of simulatingheat flow through a bed of monodisperse particles without cracks. Colour represents particle temperatures going fromred (hot) to blue (cold).
Our project focuses on exploring this discrepancy and formulating a thermophysical model of the boulders including cracks and sintering. To understand the thermophysical properties of asteroids, we base our model on the
LIGGGHTS(R)-PUBLIC package [9]. It is an open source discrete element method particle simulation software built
for simulating general granular motion and atomic/molecular dynamics. The program integrates Newton’s equationsof motion for a large collection of spherical particles which interact via short or long range forces. The inter-particle
forces are determined based on a user selected contact model which can encompass interactions such as elastic (contact) forces, rolling friction, cohesion and surface geometry of particles. In addition to mechanical interactions, thepackage can also be used to study the thermal energy transport between particles in contact. This is governed by1the thermal conductivities of the particles and their contact areas. Here we specify contact areas as the cross sectionof the geometrical overlap of two spherical particles. Upon introducing cracks in a random packing of monodisperse
particles (middle panel in Fig. 1), we intend to study the thermal properties of the bulk material.
As a benchmark test for the numerical code we calculate the steady-state heat flow through a particle-bed toreproduce the relation between thermal conductivity, contact areas, and particle radii. Once in thermal equilibrium,
thermal conductivity of the bed can be calculated given the specified temperature boundary conditions and resulting
heat flux through the bed. This can then be compared to analytical and experimental results for monodisperse
particles [10]. First results of the simulation are shown in the right hand panel of Fig. 1 where heat is flowing
vertically downwards through a bed of cohesion-less particles with adiabatic boundary conditions elsewhere.
Once the numerical method has been benchmarked using monodisperse cohesion-less particles, we will include
polydisperse particles and a parameterized description of enhanced heat transport through inter-particle bonds. Using
the contact area as a tuning parameter we fit the numerical results to the thermal properties, as derived from sample
analysis [5]. Then, cracks will be introduced as outlined in the middle panel of Fig. 1 and the associated reduction inthermal conductivity will be investigated. In this way, we will systematically study the amount of material disruption
necessary to match the remote sensing observations [7, 6, 4].

References[1]

Sei-ichiro Watanabe et al. In: Space Science Reviews 208.1 (July 2017), pp. 3–16.

[2]

Katharina Otto et al. In: Earth, Planets and Space 75.1 (Apr. 2023), p. 51.

[3]

M. Grott et al. In: Space Science Reviews 208.1 (July 2017), pp. 413–431.

[4]

Tatsuaki Okada et al. In: Nature 579.7800 (Mar. 2020), pp. 518–522.

[5]

T. Nakamura et al. In: Science 379.6634 (2023), eabn8671.

[6]

Maximilian Hamm et al. In: Planetary and Space Science 159 (2018), pp. 1–10.

[7]

M. Grott et al. In: Nature Astronomy 3.11 (Nov. 2019), pp. 971–976.

[8]

Yuri Shimaki et al. In: Icarus 348 (2020), p. 113835.

[9]

Christoph Kloss et al. In: Progress in Computational Fluid Dynamics 12.2-3 (2012), pp. 140–152.

[10]

N. Sakatani et al. In: AIP Advances 7.1 (Jan. 2017), p. 015310.

2

Defect and exsolution microstructures in four pyroxene-rich grains from Itokawa
Falko Langenhorst1,2, Agnese Fazio1, and Dennis Harries3
1Analytical Mineralogy of Nano- and Microstructures, Institute of Geoscience, Friedrich Schiller University Jena, Germany
2Hawai’i Institute of Geophys. and Planetology, School of Ocean and Earth Science and Technology, University of Hawai’i at Manoa, USA
3European Space Resources Innovation Centre, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422Belvaux,

Luxembourg

Introduction: In 2010, the Hayabusa spacecraft returned precious regolith grains from the rubble pile asteroid 25143 Itokawa.
Subsequent investigations confirmed the link between LL4-6 ordinary chondrites and the S-type asteroid Itokawa and revealed
its eventful past [1, 2]. The processes reported in regolith grains comprise thermal annealing in the original parent body and thefull range of space weathering effects from surface amorphization by ion bombardment to collisional fragmentation [2-6].
Pyroxenes, the second most abundant phase in ordinary chondrites, are an important source of information on these processes,
as they develop various process-indicative defects. Thus, we pursued here a systematic study of the microstructures in orthoand clinopyroxene grains from Itokawa and discuss the results in terms of thermal metamorphism and space weathering.
Samples and methods: In the context of the 4th International Announcement of Opportunity for Hayabusa sample
investigation, we have obtained four pyroxene-containing Itokawa particles: RB-QD04-0092, RA-QD02-0205, RB-CV-0192,
and RB-CV-0144 [7]. These grains were cut by focused ion beam (FIB) preparation on a scanning electron microscope (SEM)
and then studied by analytical transmission electron microscopy (TEM), following the procedure described by [6].
Results: RB-QD04-0092 is a flat grain (29 x 26 x 12 μm) consisting of orthopyroxene (En78Fs21Wo1) and olivine (Fo71-78).
Both olivine and orthopyroxene show defects that are compatible with local shock metamorphism, i.e. olivine contains [001]dislocations, while orthopyroxene is pervaded by multiple (100) clinoenstatite lamellae. The regolith grain shows a 40-70 nm
wide continuous damaged rim due to solar wind irradiation.
RA-QD02-0205 is a prismatic grain (55 x 43 x 15 µm) that only consists of a single crystal orthopyroxene (En74Fs24Wo2). The
dominant defects are also pervasive (100) clinoenstatite lamellae, which are decorated by partial dislocations. The grain issurrounded by a 50 nm thin polynanocrystalline rim.
RB-CV-0192 is also prismatic in shape (19 x 10 x 8 µm), and contains both orthopyroxene (En76Fs23Wo1) and clinopyroxene(En50Fs7Wo43). Adjacent olivine, plagioclase, and whitlockite were detected, too. Besides (100) clinoenstatite lamellae inorthopyroxene there are no other defects. The solar wind damaged polynanocrystalline rim is up to 50 nm thick.
RB-CV-0144 is 17 x 12 x 5 µm in size and contains both orthopyroxene (En79Fs20Wo1) and clinopyroxene (En50Fs6Wo44). The
pyroxenes possess subgrain boundaries and are traversed by thin (up to 10 nm) (100) exsolution lamellae. One side of theentire regolith grain displays a polynanocrystalline and layered rim of up to 60 nm thickness.
Discussion: The presence of amorphous to nanocrystalline rims documents the solar wind damage of Itokawa grains.
Moreover, the occurrence of shock defects in localized areas of olivine and pyroxenes (clinoenstatite lamellae anddislocations) as well as the absence of microcraters on their surfaces indicate that cascades of collisions took place in theregolith. As consequence of active space gardening the effective exposure time of regolith grains must have been reduced. Of
particular interest is the observation of thin exsolution lamellae in pyroxene, whose width of up to 10 nm points to slow
cooling rates of < 1 °C per 1000 years at peak temperatures of 800°C [2, 8].
Acknowledgements: We thank JAXA for providing access to the Itokawa particles. FIB-TEM facilities at FSU Jena were
funded by the Gottfried-Wilhelm-Leibniz award to FL (LA 830/14-1). AF is grateful to the Alexander von Humboldt
Foundation for a postdoctoral grant.
References[1] Noguchi T., et al. 2011 Science 333:1121. [2] Nakamura T. et al. 2011 Science 333:1113. [3] Keller L.P. and Berger E.L.
2014 Earth Planets and Space 66:71. [4] Noguchi T., et al. 2014 Meteoritics & Planetary Science 49:188. [5] Harries D. andLangenhorst F. 2014 Earth Planets and Space 66:163. [6] Langenhorst F., et al. 2014 Earth Planets and Space 66:118. [7] Fazio
et al. 2020 Vol.14, EPSC2020-645. [8] Weinbruch S. and Müller W.F. 1995 Geochimica et Cosmochimica Acta 59: 3221.

Asteroid Itokawa … but when did form exactly?
F. Jourdan1, N.E. Timms1, T. Nakamura2, W.D.A. Rickard1, C. Mayers1
1
Curtin University, Perth, GPO Box U1987, WA, Australia
2
Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan
Rubble piles asteroids consist of reassembled fragments from shattered monolithic asteroids and are much moreabundant than previously thought in the solar system. In earlier studies (1, 2), we analysed five regolith dust
particles recovered by the Hayabusa space probe from the rubble pile asteroid 25143 Itokawa, using a workflow
of microstructural analysis by electron backscatter diffraction (EBSD), element mapping by time-of-flightsecondary ion mass spectrometry (ToF-SIMS ± atom probe) and 40Ar/39Ar geochronology. We showed that
Itokawa must have formed before or at ca. ≥ 4. 2 Ga and concluded that rubble pile asteroids can survive
ambient solar system bombardment processes for extremely long periods. Here, we continue our quest tounderstand the bombardment history of Itokawa with the so far seemingly elusive goal of precisely pinpointing
the age and nature of the catastrophic breakup of Itokawa’s parent body. Only through a larger number of40
Ar/39Ar ages on single particles and U/Pb ages on phosphate grains (3) coupled with careful particle
characterizations, will we be able to achieve this goal. With that in mind, we analysed three new particles.
RA-QD02-0300 (dia. = 190 µm) is composed of olivine, plagioclase, with minor troilite. EBSD and ToF-SIMS
analyses show that the plagioclase in this particle is distributed in vein-like structures and has a finepolycrystalline texture of <10 µm grains with abundant inclusions and K-rich exsolutions. This suggests it
represents recrystallised melt domains. Olivine crystals show no sign of shock deformation. We obtained aplateau age of 4130 ± 33 Ma (P = 0.55). Noticeably, this age is very similar to previous results from otherparticles at 4219 ± 35 and 4149 ± 41 Ma (1), indicating an age concentration around that time. Could it be thatthe parent body of Itokawa broke up at ca. 4.2 Ga while some of the impact heated material slowly cooled down
inside the newly formed insulating rubble pile asteroid over ca. 100 million years? This scenario is tantalizing as
it would be similar to the scenario proposed by (4) for the breakup of an initially hot chondritic parent body at
4.5 Ga and with subsequent debris cooling at rates of ca. 1 to 10 °C/Ma inside the rubble pile asteroids.
RA-QD02-0306 (160 µm) is composed of olivine and plagioclase with minor troilite and chromite. This particle
is the only 40Ar/39Ar-dated particle which contains measurable solar wind, with a 38Ar/36Ar ratio of 0.188 ±0.049 (2σ) that is indistinguishable from modern solar wind value. Along with the presence of abundant microcraters, melt drop and blisters observed on the surface of the particle observed by (5), this indicates that thisparticle spent some time directly at the surface of the asteroid. This particle shows a structured 40Ar/39Ar age
spectrum, with two different portions attributed to the gas released by the plagioclase and olivine phases.
Plagioclase yielded a mini-plateau (59 % 39Ar released) age of 4557 ± 61 Ma (P = 0.71) similar to the U-Pb
phosphate age of 4640 ± 360 Ma obtained by (3) on another particle, suggesting that it recorded the initialcooling deep inside Itokawa’s parent asteroid and was not affected by heat during the breakup process. This
demonstrates that, during the breakup of Itokawa’s parent body, part of the asteroid experienced minimum tonegligible shock pressure and temperature increase. This is similar to the conclusions reached via impact
modelling calculated for the rubble pile asteroid Ryugu (6). This is also in excellent agreement with breakup
models of structurally weakened monolith asteroids that do not require a particularly large impactor to shatter(7).
RA-QD02-0311 (108 µm) is composed of olivine, Ca-rich pyroxene, plagioclase and troilite. Elemental maps
show that this particle contains very little plagioclase compared to the other particles and most of the K is
contained in a rim-like structure exposed at the edge of the particle. Olivine crystals show no sign of shock
deformation, yet 40Ar/39Ar dating reveals a complex age spectrum with maximum weighted-mean age of 705 ±53 Ma (P=0.39) including 47% of 39Ar released and indicating an impact ≤ 0.7 Ga. This maximum age, coupledwith an available impact age of 2291 ± 139 Ma (2) and maximum age estimates (1, 8), suggests that impact
events happened many times during the history of Itokawa and that the high porosity of the rubble pile material
was able to convert low-shock events into high temperature spikes, sufficient to reset and/or partially reset the40
Ar/39Ar chronometer (2) in some material.
In summary, we propose that Itokawa’s parent body was disrupted ca. 4.2 billion years ago in a process
involving heterogenous temperature distribution during the impact. Some of the heated material, mixed withcold material, cooled down inside a larger version of Itokawa, possibly over a period of ca. 100 Ma. Itokawa
kept being bombarded and eroded by small impactors since its formation with some of these events recorded by
the 40Ar/39Ar system.
References[1] Jourdan et al. 2023. Proceedings of the National Academy of Sciences 120, e2214353120. [2] Jourdan et al.,2017. Geology 45, 819-822. [3] Terada et al., 2018. Scientific Reports 8, 11806. [4] Lucas et al., 2020. Geochim
Cosmochim Ac 290, 366-390. [5] Matsumoto et al., 2018. Icarus 303, 22-33. [6] Nakamura et al., 2022. Science
379, eabn8671. [7] Michel et al. 2004. Icarus 168, 420-432. [8] Park et al., 2015. Meteoritics and Planetary
Science 50, 2087-2098.

Characterization of a mass movement site in Bennu’s Bralgah Crater and implications for other asteroids
Yuhui Tang1, D.S. Lauretta1, R.-L. Ballouz2, D.N. DellaGiustina1, C.A. Bennett1, D.R. Golish1
1
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
2
The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.
Near-Earth asteroids such as Bennu and Ryugu have boulder-covered surfaces and latitude-dependent slope
distributions, signifying that mass movements of boulders perform significant roles in the surface evolution of these small
bodies. The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission[1] documented numerous locations on Bennu exhibiting evidence of mass movements of surface material, mostly towards thelower elevation equatorial region [2]. One such location, contained within Bralgah Crater, was considered (but not used) by the
mission as a candidate site for sample collection; thus, high-resolution images collected during reconnaissance of this area
allow a more detailed survey than would be possible elsewhere [3] [Fig. 1]. An apparent flow “wake” downhill from a 4.8-mdiameter central boulder in the area, where medium-sized boulders are much less prevalent than in the surrounding terrain,provides an opportunity to investigate the characteristics of mass flow on the asteroid. Through boulder mapping andtopographic analysis, we found evidence of a pileup behind the central boulder, as well as a strong orientational preference ofthe boulders in this area [Fig. 2]. This preferential long-axis orientation exhibits the same westward deflection from theexpected downslope direction that we observed at another mass movement site in Bennu’s northern hemisphere [4], implyingthat a global mechanism with effects mirrored between the northern and southern hemispheres is affecting the mass flows.
We performed dynamical simulations of seismic shaking using the discrete-element N-body code PKDGRAV [5–8]to better constrain the conditions that may have formed the landscape. In these simulations, we used boulder sizes similar to
those surveyed at the Bralgah Crater site and an environment with a similar 4.8-m-diameter central boulder. We were able toreplicate the pileup of material uphill from the central boulder and the wake downhill from it, producing similar elevation
profiles created by a lack of downflowing material in the wake area [Fig. 3].
Simulations also showed a preferential orientation emerging, with a strong possibility for preferential orientation
parallel to direction of motion. Combined with the orientational preference observed in this and other studies of Bennu’s
landscape, this indicates that the Coriolis effect could be a major factor in the mass movement of boulders and would help to
explain the westward deflection of the boulders’ long-axis orientation. Numerical simulations show that the Coriolis effect isstrong enough to induce an east-west displacement of the boulders, which can amount to 10% of the downslope displacement,
which could lead to the observed orientational preferences. This effect would be expected to occur on other fast-spinning
asteroids, such as Ryugu, where this hypothesis predicts a similar orientational preference, with eastward deviation from thepoleward migration of the boulders.

Figure 1. A map of the survey area (magenta outline) within Bralgah Crater, projected in ArcGIS, with the central boulder (long axis, 4.8 m)
highlighted by the light blue best-fit ellipse. The downhill direction is north in this area.

Figure 2. Orientations of the surveyed boulders as a rose diagram (A) and histogram (B), with the data best fitted by a bimodal von Mises
distribution (green) with peaks at 94.1° and 164.2° (p-value = 0.839). (C) The empirical distribution function (black line) and cumulative
distribution function (green line) of the orientations, used for the K-S tests to derive the p-values.

Figure 3. (A) Elevation map of the study site, overlayed with arrows indicating the direction of greatest slope, with the locations of theelevation profiles along longitudes 321°E and 323°E marked in cyan and orange, respectively. (B) The elevation profiles indicated in (A),with the 321°E line profile (cyan) crossing the middle of the central boulder. The blue dashed line represents the best-fit slope of the pileup
area uphill from the central boulder, extrapolated across the entire mass movement length. The extrapolated profile ranges from 0.8 to 1.6 m
above the actual elevation profile downhill from the central boulder, with greater differences further north (downhill). (C) Elevation profile
of simulations after one shaking. The cyan solid line shows elevation along the center of the wake, and the orange dashed-dot line shows theelevation along a parallel transect away from the wake.

References[1] Lauretta, D. S., et al. (2017). OSIRIS-REx: Sample Return from Asteroid (101955) Bennu. Space Science Reviews, 212(1–2), 925–984. https://doi.org/10.1007/s11214-017-0405-1[2] Jawin, E. R., et al. (2020). Global Patterns of Recent Mass Movement on Asteroid (101955) Bennu. Journal of GeophysicalResearch: Planets, 125(9). https://doi.org/10.1029/2020JE006475[3] Lauretta, D. S., et al. (2021). OSIRIS-REx at Bennu: Overcoming challenges to collect a sample of the early Solar System.
In Sample Return Missions (pp. 163–194). Elsevier. https://doi.org/10.1016/B978-0-12-818330-4.00008-2[4] Tang, Y., et al. (2023). Simulating impact-induced shaking as a triggering mechanism for mass movements on Bennu.
Icarus, 395, 115463. https://doi.org/10.1016/j.icarus.2023.115463[5] Ballouz, R.-L. (2017). Numerical Simulations of Granular Physics in the Solar System [Ph.D., University of Maryland,College Park].
[6] Richardson, D. C., Quinn, T., Stadel, J., & Lake, G. (2000). Direct Large-Scale N-Body Simulations of Planetesimal
Dynamics. Icarus, 143(1), 45–59. https://doi.org/10.1006/icar.1999.6243[7] Schwartz, S. R., Richardson, D. C., & Michel, P. (2012). An implementation of the soft-sphere discrete element method ina high-performance parallel gravity tree-code. Granular Matter, 14(3), 363–380. https://doi.org/10.1007/s10035-012-0346-z[8] Zhang, Y., et al. (2017). Creep stability of the proposed AIDA mission target 65803 Didymos: I. Discrete cohesionlessgranular physics model. Icarus, 294, 98–123. https://doi.org/10.1016/j.icarus.2017.04.027

Photometry of Ryugu and SCI crater as inferred by ONC images
A. Longobardo1, M. Angrisani1, E. Palomba1, F. Dirri1, Y. Yokota2, T. Kouyama3, R. Honda4 and the Hayabusa2/ONC
Team
1

INAF-IAPS, via Fosso del Cavaliere 100, 00133 Rome, Italy
JAXA-ISAS, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara City, Kanagawa Prefecture, 252-5210, Japan
3
National Institute of Advanced Industrial Science and Technology, Umezono 1-1-1, Tsukuba, 305-8568, Japan;
4
Kochi, University, Kochi, Japan
2

The JAXA/Hayabusa2 rendezvoused with the Ryugu asteroid from June 2018 to November 2019, performing an
artificial impact experiment on 5th April 2019.
The goal of this work is to study the photometric properties’ variation of the target area (latitude 4.5-10°N; longitude299-305°E) after the artificial impact experiment. This is done by applying an empirical method based on the statisticalanalysis of the ONC camera’s dataset (in particular, the v band, centred at 0.55 m), similar to that applied to several
asteroids (e.g., Longobardo et al., 2014; 2018) and to the NIRS3 dataset of Ryugu (Longobardo et al., 2022).
The method has been firstly applied on the entire dataset acquired between March and April 2019, covering most of the
Ryugu surface. The first step was the retrieval of the equigonal albedo, by applying the Akimov disk function. The
obtained equigonal albedo is independent of incidence and emission angle when phase angle is lower than 60°, while aslight dependence is still present for larger phase angles.
Then, the average phase function of Ryugu was obtained. This is very similar to that obtained on the NIRS3 dataset(i.e., in a different spectral range), according to our expectations.
Then, we calculated two photometric parameters R20 (i.e., the radiance factor at 20° phase) and PCS1540 (i.e., the phasefunction steepness between 15° and 40° phase angles) and compared them to photometric parameters calculated onphase functions of other asteroids visited by space missions and on both disk-integrated and disk-resolved phasefunctions of Ryugu obtained by Tatsumi et al. (2019). The disk-resolved phase functions by Tatsumi et al. (2019) andobtained in this work are in good agreement.
Nevertheless, the Ryugu’s disk-resolved phase function is much flatter than other dark asteroids. Otherwise, the diskintegrated phase function of Ryugu is in good agreement with other dark asteroids. This is the ascribed to the fact thatdark bodies’ phase function flattens with improving spatial resolution due to the reducing role of shadowing. A similar
behaviour was observed on other dark asteroids, i.e., Ceres (Longobardo et al., 2019) and Bennu (Golish et al., 2021).
Finally, we focused the analysis on the artificial impact area by comparing phase curves before and after the impact.
Currently, the only variations observed are within uncertainties, but we need to enlarge the dataset before to give any
definitive conclusion.
Acknowledgements. We thank the ONC development/operations Team.
References
Golish et al. (2021), Icarus 357, 113724
Longobardo et al. (2014), Icarus 240, 20-35
Longobardo et al. (2019), Icarus 320, 97-109
Longobardo et al. (2022), A&A 666, A185
Tatsumi et al. (2019), A&A 639, A83

The shape distributions of sub-mm-sized impact experiment fragments from Allende meteorite
Tatsuhiro Michikami1, Akira Tsuchiyama2,3,4, Axel Hagermann5, and Sunao Hasegawa61

Faculty of Engineering, Kindai University, Hiroshima Campus, 1 Takaya Umenobe, Higashi-Hiroshima, Hiroshima 739-2116,
Japan, (michikami@hiro.kindai.ac.jp), 2Research Organization of Science and Technology, Ritsumeikan University, 1-1-1
Nojihigashi, Kusatsu, Shiga, 525-8577, Japan, 3CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial
Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (CAS),
511 Kehua Street, Wushan, Tianhe District, Guangzhou, 510640, China, 4CAS Center for Excellence in Deep Earth Science,
Guangzhou 510640, China, 5Luleå University of Technology, Space Campus, 981 28 Kiruna, Sweden, 6Institute of Space andAstronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-8510, Japan.
Several spacecraft have shown that kilometer-sized or smaller asteroids, such as Itokawa, Ryugu and Bennu, are covered withregolith particles. The shapes of regolith particles are considered clues to understanding their formation and evolution on asteroid
surface. Ryugu particles are likely fragments resulting from impacts on the asteroid's surface. However, there has been a lack oflaboratory impact experiments specifically examining the shapes of fragments in carbonaceous chondrites, which originate fromcarbonaceous asteroids like Ryugu and Bennu. In this study, we take the first step towards a better understanding of the shapesof impact fragments in carbonaceous chondrites. We conducted an impact experiment on the carbonaceous meteorite Allendeand investigated the shape distributions of sub-mm-sized impact fragments using X-ray microtomography. As a result, weobserved many fragments cross-sections along the chondrule boundary. In addition, these fragments tended to be rounder thanpreviously observed impact fragment shapes. However, because the total number of these fragments is relatively small, theoverall shape distribution of the fragments was found to be the same as that of previous impact fragment shapes. This finding
will be useful for understanding the formation process of regolith layers on the asteroid surface, Itokawa particles, Ryugu
particles, and Bennu particles scheduled to return to Earth.

Spectral characterization of (98943) 2001 CC21, fly-by target of Hayabusa2#
Perna D.1, Barucci M.A.2, Belskaya I.2,3, Birlan M.4,5, Bourdelle de Micas J.1, Dotto E.1, Fornasier S.2, Hasegawa S.6, Ieva S.1,
Inasaridze R.7, Ishiguro M.8, Kitazato K.9, Krugly Yu.3, Kuroda D.10, Mazzotta Epifani E.1, Palomba E.11 and Yoshikawa M.4
INAF – Rome Observatory, Italy. 2LESIA – Observatoire de Paris, France. 3Kharkiv National University, Ukraine. 4IMCCE –Observatoire de Paris, France. 5Astronomical Institute of the Romanian Academy, Romania. 6ISAS-JAXA, Japan. 7E.
Kharadze Georgian National Astrophysical Observatory, Abastumani, Georgia. 8Seoul National University, South Korea.
9
Aizu University, Japan. 10Japan Spaceguard Association, Japan. 11INAF-IAPS, Italy

1

To help solving uncertainties about the surface composition and possible heterogeneity of asteroid (98943) 2001 CC21, next
fly-by target of Hayabusa2#, we acquired new visible and NIR photometric and spectroscopic data.
Visible (BVRI) spectrophotometry was obtained on November 2022 in the framework of the European NEOROCKS project,using the 1.2-m telescope located at the Haute-Provence observatory in France. Details of the observations and data reduction
are given in [1]. The measured colors are within the range of values typical for S-complex. Figure 1 shows a comparison of thespectral behaviors of 2001 CC21 and templates of Sq, Sr, L and K-types according to the Bus-DeMeo classification scheme [2].
Our observations are well consistent with Sq or Sr types and do not support a L-type classification. This result is in agreementwith recently published data on polarimetry and near-infrared spectrometry of this asteroid [3].
On January-February 2023, we also used the 2.6-m NOT telescope (La Palma, Canary Islands, Spain) to acquire visible spectra
and NIR photometry of 2001 CC21 at different rotational phases. These data, currently under reduction, will allow us to further
constrain its surface composition and possible heterogeneity.
On January 22, 2023 we observed 2001 CC21 in R band and covered the whole rotational period (Fig.2). The CCD
observations were carried out using the 0.7-m telescope at the Abastumani Astrophysical Observatory, Georgia. The lightcurve
amplitude is 0.75 mag and Prot ⁓ 5.03 hours.
Preliminary results confirm the S-complex taxonomy, and suggest a subtle spectral variation with the rotational phase. An
overview of our results will be presented and discussed at the Symposium.

Figure 1.

Comparison of 2001 CC21 obtained data with

Figure 2.

Lightcurve obtained on Jan 22, 2023.

different asteroid taxonomic templates [4].

References[1] Hromakina et al. 2021. MNRAS 520:3143. [2] DeMeo F. et al. 2009. Icarus 202:160. [3] Geem J. et al. 2023. MNRAS
525:L17. [4] Barucci at al. 2023. Abstract #2015, ACM 2023.

Asteroid (142) Polana at 3 µm and its Connection to Primitive Near-Earth Asteroids
Driss Takir1
Jacobs, NASA JSC
Introduction: Impacts between asteroid-sized objects have dominated the solar system's history and played a significant rolein forming asteroid families. The New Polana family is a low-inclination and the most prominent low-albedo family within the
inner Main Belt between the v6 secular resonance at ~2.0 AU and the 3:1 mean-motion resonance with Jupiter at ~2.5 AU [1].
This family formed over 2000 Myr ago and is parented by the B-type asteroid (142) Polana [1]. [2] and [3] found that primitivenear-Earth asteroids (NEAs), including Hayabusa2’s asteroid target (162173) Ryugu and OSIRIS-REx’s asteroid target(101955) Bennu, are likely disrupted fragments that originated during the formation of the New Polana family. Other possible
sources of primitive NEAs in the inner Main Belt include the Clarissa, Erigone, Polana, and Sulamitis, families and thecollisionally evolved background asteroids outside these families [2, 4].
The age of the solar system is longer than the collisional lifetime of asteroid Bennu [5], a rubble pile asteroid with amean diameter of 490.06 ± 0.16 m [6] and a spinning top-like shape [7]. Asteroid 142 Polana, the largest remnant of the New
Polana family [1], has been spectrally (~0.5-2.5 µm) and dynamically linked to asteroid Bennu [e.g., 2]. Bennu’s spectra were
measured over the wavelength range from 0.4 to 4.3 µm with OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS) [8].
Here, we investigate the compositional linkage of asteroids Polana and Bennu using 3-µm Polana spectra measured at theInfrared Telescope Facility (IRTF).
1

Results: Polana's prism (0.7- 2.5 µm) spectra
exhibit a broad concave feature centered~1.21 µm with a band depth of ~11%. The
spectrum has a slight positive slope toward
wavelengths greater than 1.2 µm. We
acquired two Prism sets of Polana, the first at
12:32 UTC and the second at 12:48 UTC on
July 2nd, 2023. Spectra of the two prism sets
are similar, showing no compositional
heterogeneity in the observed surface of
Polana. On the other hand, Polana's LXD(1.9– 4.2-µm) spectra do not reveal any
pronounced spectral features in the ~2.0-4.0µm spectral range, suggesting that thisasteroid is not hydrated (Figure 1).
Figure 1. Spectra of asteroids Bennu and Polana. The ~1.2-µm band in Polana is
more pronounced than in Bennu. Bennu’s spectrum is an average
spectrum measured at the 10:00 a.m. station. Unlike Bennu, Polana does not show
a pronounced feature at ~3-µm. Slope-removed spectra are normalized at 2.2 µm.

Discussion: Prism’s spectrum of Polana shows a broad feature centered around 1.2 µm (Figure 1), possibly due to amorphousiron-rich silicates abundant in least-processed CO carbonaceous chondrites that experienced minimal aqueous alteration andthermal metamorphism [10, 11]. Magnetite was also suggested to cause the 1.2-µm feature in B-type asteroids [12]. The 1.2µm feature in the Polana spectrum is much deeper and more pronounced than Bennu's, suggesting that Polana has moreabundant amorphous silicates or magnetite on its surface than Bennu. Polana was previously observed by [13], and its spectra
SNR did not allow the authors to confirm the presence of a feature at ~3-µm. In this work, the LXD spectrum of Polana wasfound to be featureless (does not exhibit a 3-µm feature within two sigma), suggesting that Polana’s surface is much lesshydrated than Bennu’s. Bennu’s spectra were measured by OSIRIS-REx’s OVIRS spectrometer, revealing that this primitive
asteroid is hydrated (the 3-µm band has a depth of ~20%) consistent with CM-, CI-, or CR-type carbonaceous chondrites [9].
In addition, Polana’s LXD spectra do not indicate the presence of organics and/or carbonates, unlike Bennu, whose spectra
were found to be consistent with carbonates dominated by calcite and aromatic and aliphatic organics with CH bonds [14, 15].
The lack of pronounced water (OH/H2O), organic materials, and carbonates features on asteroid Polana could be
related to the degree of heating produced by shock metamorphism during the New Polana family-forming event and the ejecta
reaccretion that contributed to additional heating. To lose most of its surface hydrated minerals, including serpentines, Polana
had to be exposed to impact temperatures higher than ~800 K [16]. Heating generated by disruptive collisions (families
forming events) is substantial, where the temperature of almost all the parent bodies increases from 300 K (initial temperature)
to 700 K [17]. [18] concluded that the hydration state of the members of a collisional family is heterogeneous and mainly
depends on the impact energy level within the family.
Several factors can affect the degree of heating and shock metamorphism during family-forming events, including theimpactor velocity and size, porosity within the asteroid's parent body, and material ejection efficiency. [19] found that in
rubble-pile asteroids, the impactor velocity and size are the main factors responsible for high-grade shock metamorphism in
impacts occurring in the Main Belt. According to these authors, changing the porosity, responsible for the overall energy

absorption within the parent body, from 10% to 30% in their simulations only slightly decreases the shock pressure andtemperature.
Another possibility for explaining the discrepancy between Polana and Bennu in the 3-µm band could be that the New
Polana family-forming event exposed the parent body's deep interior. The dislodged Bennu fragment from the parent bodycontains phyllosilicates, organics, and carbonate, unlike the exposed interior of the parent body that does not include thesematerials.
Laboratory experiments on carbonaceous chondrites have shown that space weathering can also affect the spectral
characteristics of these chondrites [20, 21]. For example, irradiating these carbonaceous chondrites can cause their nearinfrared spectra to become bluer and brighter or redder and darker depending on several factors, including their initial albedo.
Space weathering can also cause the band depth of mineral absorptions at 0.7 and 3.0 µm to decrease receptively by 12 % to50% [22]. Space weathering could cause the band depth at 3.0 µm to degrade significantly over time. The New Polana is oneof the older families in the Main Belt (~2000 Myr, [1]). Near-Earth asteroids’ lifetimes are ~10 Myr [3]; therefore, Bennu
would have been less exposed to space weathering than Polana was.
Exogenic materials and breccias are common in NEAs (e.g., [23]). Exogenous basaltic materials were discovered on
the rubble pile asteroid Bennu, linked to inter-asteroid mixing that occurred at macroscopic scales after the end of theplanetesimal formation [24]. It is possible that exogenic hydrated (in addition to basaltic) materials landed on Bennu,
contributing to its hydration level.
Remote sensing observations of the primitive NEAs Ryugu and Bennu suggested that these two asteroids experienceddifferent aqueous alteration histories, as revealed by the characterization of their surface composition using the 3-µm band.
The NIRS3 instrument on board hayabusa2 detected a weak and narrow absorption feature centered around 2.27 µm across theobserved Ruguy’s surface, attributed to hydroxyl-bearing minerals [25]. Returned samples from Ryugu confirmed that thisasteroid has a similar composition to CI-type carbonaceous chondrites [26]. OSIRIS-REx’s OVIRS detected a broader anddeeper 3-µm band in Bennu compared to NIRS3 observations of Ryugy. Based on their 3-µm hydration features, it is more
likely that Ryugu and Bennu came from different parent bodies with distinct aqueous alteration and thermal histories. With thecurrent ground-based observations of Polana and due to strong Earth atmospheric absorptions that affect the ~2.7-µm region, it
is not feasible to fully assess if this asteroid has a 3-µm band like the narrow and subtle band found in Ryugu. An approved
JWST program to observe Polana (with the NIRSpec and MIRI instruments) will allow us to further investigate Polana's
connection to Bennu and Ryugu.
References: [1] Walsh, K.J et al. 2013. Icarus 225, 283–297. [2] Campins, H. et al. 2010, ApJ, 721, L53. [3] Bottke, W. F etal. 2015, Icarus, 247, 191. [4] Arredondo, A. et al. 2021. Volume 368, 1. Icarus. [5] Bottke, W. F. 2015et al. Icarus 247, 191271. [6] Barnouin, O. S. et al. 2019. Nat.Geosci. 12, 247–252. [7] Lauretta, D. S. et al. 2019 Nature 568, 55–69. [8] Reuter, D.
C. et al. 2018. Space Sci. Rev., pp. 214, 54. [9] Hamilton, V. E et al. 2019, Nat. Astron., 3, 332. [10] Cloutis, E.A. et al.
2012. Icarus 220, 466–486. [11] McAdam, M. and Gustafsson, A. 2021. Icarus 369 (2021) 114592. [12] Yang, B., Jewitt,
D.2010. The Astronomical Journal, 140:692–698. [13] Rivkin, A. S. et al.2022 Planet. Sci. J. 3, 15. [14] Kaplan, H. H. et al.
2020, Science, 370, eabc3557. [15] Kaplan, H.H. et al. 2021. A&A 653, L1. [16] Nakamura, T. Yamato 2016. Earth Planet.
Sci. Lett. 242, 26–38. [17] Davison, T.M et al. 2010. Icarus 208 468–481. [18] Michel, P. 2020. et al. Nature Communications
volume 11, Article number: 2655. [19] Güldemeister et al. 2022. The Planetary Science Journal, 3:198 (12pp). [20] Lantz et al.
2018. Space weathering trends on carbonaceous asteroids: possible explanation for Bennu’s blue slope? Icarus 302, 10–17.
[21] Thompson, M. S. et al. Icarus 319, 499-511. [22] Matsuoka, M.et al. ApJL 890 L23. [23] Bischoff, A. et al. 2010.
Meteorit. Planet. Sci. 45, 1638–1656. [24] DellaGiustina et al. Nature Astronomy, 5, January 2021 | 31–38. [25] Kitazato et al.
2019. Vol 364, Issue 6437 pp. 272-275. [26] Yada et al. 2021. Nature Astronomy volume 6, pages214–220.

Unveiling dark objects in Solar System: grain size effects on the infrared spectrum of mineral
mixtures in presence of opaque components
G. Poggiali1,2, L. Fossi2, A. Wargnier1, J. Beccarelli3, J.B. Brucato2, M.A. Barucci1, P. Beck4, M. Matsuoka5, T. Nakamura6, M.
Pajola3, S. Fornasier1,7, F. Merlin1, A. Doressoundiram1, T. Gautier8 and G. David1
1
LESIA-Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris Cité, 92195 Meudon
Principal Cedex, France (giovanni.poggiali@obspm.fr)
2
INAF-Astrophysical Observatory of Arcetri, Firenze, Italy3
INAF-Astronomical Observatory of Padova, Padova, Italy
4
Institut de Planétologie et d’Astrophysique de Grenoble, OSUG/CNRS, Grenoble, France
5
The Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
6
Department of Geophysics, Tohoku University, Sendai Miyagi, Japan
7
Institut Universitaire de France (IUF), 1 rue Descartes, F-75231 Paris Cedex 05, France,
8
LATMOS, CNRS, Sorbonne Université, Université Versailles St-Quentin, Guyancourt, France
Dark surfaces characterize several bodies in the Solar System: from primitive carbonaceous asteroids to the enigmatic surfaceof Phobos and Deimos, our knowledge on the spectroscopic behaviour of low albedo surfaces is still incomplete. A dark
surface can be related to multiple factors, for example presence of opaque material [1] or strong surface alteration [2]. In order
to interpret remote sensing data, laboratory studies remain a pivotal tool to unveil the surface physical state and composition.
Several processes can be simulated in the laboratory, but the preparation and analysis of complex mixing of analog material isone of the most fundamental tool and, at the same time, one of the most complex study when multiple components are used. In
this work, we aim to study how dark material
mixed with basaltic material at different grain sizes
can affect the spectroscopic features from near- to
mid-infrared (1.25-25 µm).
Our sample set includes four series of basaltic mix(feldspar and pyroxene), at different grain sizes
from < 50 µm to 1000 µm, mixed with amorphous
carbon at increasing weight percentages from 1%
to 50%. We analysed several features on the
spectrum of each mineral mixture: (i) near infraredslope; (ii) 2.7 µm OH-stretching band; (iii)
Christiansen features; (iv) Reststrahlen band andTransparency feature. Measurements presented inthis work [3], for the first time take into account alarge wavelength range and point towards a criticaleffect of dark material with a different outcome foreach grain size. Some of the most interesting
results involved the slope and the different
behaviour of the Reststrahlen band. This dataset
will be a good support in the interpretation of
Figure 1. Infrared spectra of basaltic mixtures [BAS] at different grain sizes,
upcoming data from Phobos Martian Moon
<50, 50-200, 200-500 and 500-1000 μm, with addition in different
eXploration mission, as well as in understanding of
proportions,from 1 to 50%, with synthetic amorphous carbon [SAC].
previous data from dark surfaces in the Solar
System like Ryugu and Bennu.
References[1] Cloutis et al 1990, Icarus, 84 (2), 315-333 [2] Hasegawa et al 2022, The Astrophysical Journal Lettes, 939, L9 [3] Poggiali
et al 2023, Astronomy & Astrophysics (submitted)

Investigating the effects of space weathering in Ryugu samples using coordinated microanalyses.

1

L. E. Melendez1, M. S. Thompson1, L. P. Keller2, S. A. Eckley3, and C. J. Snead2
Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN (melendl@purdue.edu)
2
ARES, NASA Johnson Space Center, Houston, TX
3Jacobs, NASA Johnson Space Center, Houston, TX.

Introduction: Airless planetary surfaces are characterized by a distinct lack of an atmosphere or magnetic field, leading todirect exposure to the effects of hypervelocity micrometeoroid impacts and solar wind ion irradiation [1]. These processes,
cumulatively known as space weathering, gradually alter the microstructural and chemical properties of the grains on airlesssurfaces. Signatures of space weathering include vesiculated textures, amorphous grain rims (upper ~100 nm), solar flare
tracks, and Fe-bearing nanoparticles (npFe) [2,3]. The accumulation of these microstructural space weathering characteristics,
particularly the presence of npFe, alters the spectral properties of airless regoliths resulting in changes in spectral slope andreflectance of the surfaces, and the attenuation of characteristic absorption bands in the visible to near-infrared (Vis-NIR)
wavelengths. These spectral changes complicate our ability to accurately interpret the mineralogy of airless bodies via remotesensing spectroscopy [1,4]. Studies of space weathering have primarily focused on anhydrous silicate minerals, reflecting themain components of the available returned samples from the Moon and S-type asteroid Itokawa [3,5,6]. However, ourunderstanding of space weathering of primitive, organic-rich carbonaceous materials is still a work in progress. The Japan
Aerospace Exploration Agency (JAXA)’s Hayabusa2 mission offered the first opportunity to directly investigate carbonaceous
asteroids by returning samples from C-type asteroid (162173) Ryugu. Initial studies of Ryugu samples show mineralogicalsimilarities to CI chondrites along with surface modifications consistent with space weathering. These surface modifications
are primarily in the form of µm-thick silicate melts, amorphized phyllosilicates, glassy spherules, and burst vesicles [3,7]. Here,
we report results from coordinated microanalytical techniques to further our understanding of the mineralogy and space
weathering of carbonaceous materials.
Samples and Methods: We have been allocated two Ryugu particles returned by Hayabusa2; one particle collected at each of
the two touchdown sites (A0152 and C0178). To understand the internal microstructure, mineralogy, and surface morphologyof the two particles, we used X-ray computed tomography (XCT) to scan the samples using the Nikon XTH 320 micro-XCT at
NASA Johnson Space Center (JSC) (Fig. 1). We also completed a higher-resolution sub-volume scan on the Zeiss Xradia 620
Versa at the University of Texas at Austin High Resolution X-ray CT Facility (UTCT) (Fig. 1). We segmented the dataset to
identify different phases (e.g., sulfide minerals) and their spatial distribution using Dragonfly software. Due to the friable
nature of the sample, small fragments were shed from the main mass during sample transport. We transferred <500 µm
fragments of each particle to SEM mounts covered with carbon tape and coated the fragments with evaporated carbon. The
stubs were characterized using the Quanta 3D FEG focused ion beam scanning electron microscope (FIB-SEM) at NASA JSC
using both backscatter (BSE) and secondary electron (SE) imaging detectors along with a 70 mm2 SDD energy dispersive Xray spectroscopy (EDS) detector (Fig. 2).
a

c

1 mm
b

1 mm
d

1 mm

1 mm

Figure 1. XCT scan of grain A0152 (a) and C0178 (b) with a resolution of 2.15 µm per voxel.
Volume renderings with bright (higher relative Z number) phases (i.e., pyrrhotite and magnetite) inyellow for A0152 (c) and C0178 (d).

a

25 µm

b

c

5 µm

5 µm

1 µm

d

e

g

5 µm

30 µm

1 µm

f

Figure 2. (a) Backscattered electron image (BEI) of one of the subparticles from A0152 with Fe1-xS (e.g., pyrrhotite (b)) and characteristic
signatures of space weathering, including (c) melt droplets and (d) vesicular textures. This melt deposit was targeted for further analysis in
the TEM, with electron transparent thin sections prepared using FIB-SEM (e). The BF STEM image from the resulting FIB section (f)shows a region with a sub-µm impact spherule on the surface on top of a darker melt layer. The composite RGB image (g) shows Mg (red),Fe (green), and S (blue), revealing a Mg-rich melt layer and a spherule with nanophase Fe and FeS inclusions.

Particles from chamber A that displayed vesicles or melt textures on their surface (indicators of micrometeoroid bombardment)
were targeted for the preparation of three focused ion beam (FIB) sections for further analysis in the scanning transmission
electron microscope (STEM). Particles from chamber C reflected the expected mineralogy of Ryugu but evidence of space
weathering has not been identified on these grains. Two FIB sections were extracted from the phyllosilicate matrix andmagnetite grains for comparison to the space-weathered regions of A0152. Bright field (BF) and dark field (DF) STEM images
and chemical maps of the FIB sections were acquired using the JEOL 2500SE STEM equipped with a 60 mm2 ultra-thinwindow silicon drift energy-dispersive EDS detector at JSC.
Discussion and Conclusions: XCT results indicate that the grain is a micro-breccia, and that hexagonal sulfide grains (likely
pyrrhotite) are ~10 to ~200 µm wide are distributed throughout the fine-grained phyllosilicate and carbonate-rich matrix.
Magnetite (Fe3O4) particles were also observed in both samples, exhibiting both framboidal and plaquette morphologies. 3D
shape (SPO) and crystallographic (CPO) preferred orientations of sulfides (Fig. 1b) are being analyzed using Blob3D and
3DGrainMapper software, respectively. Currently, surface mesh renderings of A0152 and C0178 are being explored forevidence of impact cratering events, following [8]. SEM analysis of fragments from A0152 revealed vesiculated melt layers
and frothy melt textures with melt spherules with embedded nanoparticles, resembling the deposits observed in simulated
micrometeoroid bombardment [9]. STEM imaging confirmed the presence of Mg-rich phyllosilicates (serpentine and saponite),magnetite with variable morphologies, sulfides, and dolomite, consistent with previous studies of Ryugu samples indicating a
low temperature aqueous alteration history [10, 11]. EDS analyses of these FIB sections of these regions revealed impact
Sulfidespherules and melt layers (up to 200 nm thick) containing abundant nanophase Fe-S and Fe-Ni-sulfides. Many of the
Beads
nanoparticles are polyphasic, as opposed to the monomineralic nanoparticles observed in experimental samples. The melt
layers have varying compositions depending on the underlying grain matrix: phyllosilicate grains have Ni-rich and Fe-poor
melt layers while carbonate grains have Fe-, Mg- and O-rich melt layers. None of the particles analyzed thus far from C0178
exhibit textures characteristic of space weathering, which may be due to the comparatively ‘fresh’ nature of the subsurface
sampling site, but we plan on proposing for additional grains for further analysis. We will continue to analyze these samples tobetter understand the effects of space weathering on carbonaceous
1 regolith in preparation for the analysis of returned samples
from asteroid Bennu by OSIRIS-REx this year.
References[1] Pieters C. M. and Noble S. K. (2016) Journal of Geophysical Research 121(10): 1865–1884. [2] Keller L. P. and McKay D.
S. (1997) Geochimica et Cosmochimica Acta 61:2331–2341. [3] Noguchi T. et al. (2014) Meteoritics & Planetary Science
49:188–214. [4] Chapman C. R. (2004) Annual Review of Earth and Planetary Sciences 32:539–567. [5] Taylor L. A. et al.
(2001) Journal of Geophysical Research: Planets 106:27985–27999. [6] Nakamura, T. et al. (2011) Science 333: 1113–1116.
[7] Matsumoto, T. et al. (2021) Hayabusa Symposium 2021. NIPR.[8] Hamann, C. et al. (2023) 86th Annual Meeting of the
Meteoritical Society Conference Abstract 2692. [9] Thompson M.S. et al. (2019) Icarus 319: 499–511. [10] Matsumoto T. et al.
(2021) Nature Communications 11:1–8. [11] Nakamura T. et al. (2022) Science 379: 6634–6785. [12] Tomioka et al. (2023)
Nature Astronomy 7: 669–677.

Impact-induced melting and fragmentation of C-type asteroid regolith
inferred from impact craters on a large Ryugu sample
C. Hamann1, E. Bonato2, A. Maturilli2, K. Mahlow1, M. Patzschke3, R. Luther1, K. Kurosawa4, G. Alemanno2,
S. Schwinger2, A. Van den Neucker2, M. Baqué2, L. Hecht1,5, A. Greshake1, and J. Helbert2
1
Museum für Naturkunde Berlin, 10115 Berlin, Germany. 2German Aerospace Centre, 12489 Berlin, Germany. 3Bruker Nano
Analytics, 12489 Berlin, Germany. 4Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 2750016, Japan. 5Institute of Geological Sciences, Freie Universität Berlin, 12249 Berlin, Germany.
The surfaces of airless planetary bodies are continually exposed to hypervelocity impacts of micrometeoroids and the influx ofsolar-wind ions as well as electromagnetic radiation emitted from the sun or other galactic sources [1,2]. Over time, theseprocesses gradually alter the morphologies, microstructures, and chemical compositions of regolith grains exposed to space [3–7], which is collectively known as space weathering. Because space weathering alters the optical properties of space-exposed
regolith (e.g., [2]), understanding space weathering of various types of planetary surfaces is critical for interpretation of remotesensing data obtained from such surfaces and for matching various meteorite types to potential parent bodies. However, while
the effects of space weathering on anhydrous regolith materials is well understood on the basis of samples returned from theMoon (e.g., [3,4]) and S-type asteroid Itokawa (e.g., [5–7]), space weathering of hydrous, carbonaceous-chondrite (C-type) likeasteroidal surfaces is poorly understood so far. Samples returned by JAXA’s Hayabusa2 mission from C-type near-Earth asteroid
Ryugu (e.g., [8,9]) allow us to directly study the processes and products of space weathering of C-type asteroid regolith. Previous
studies demonstrated that the uppermost surfaces of regolith grains returned from Ryugu’s surface are amorphous and dehydrated
due to influx of solar-wind ions [10,11]. In addition, small microcraters typically less than 10 µm across and splashes of quenchedmelt—presumably impact melts—have been reported from several Ryugu samples [10,12]. To better understand the role ofmicrometeoroid impacts in space weathering of C-type asteroids, we studied the impact-crater population on Ryugu sample
A0112, which is a large (3.0 × 1.8 mm) regolith grain collected at the first touchdown site from the asteroid’s immediate surface.
Scanning electron microscopy (SEM) at Museum fürNaturkunde Berlin, Germany and Bruker Nano Analytics,
Berlin, Germany as well as X-ray micro-computed
tomography (μCT) at Museum für Naturkunde Berlin
revealed the presence of three large, crater-like
depressions of 150–270 μm diameter as well as of several
smaller, circular pits of between 5 and 20 μm diameter on
one of the surfaces of A0112 (Fig. 1). High-magnification
SEM imaging furthermore revealed the presence of frothy,
highly vesicular materials that are interpreted as quenched
impact melts (cf. [10]) lining the bottoms and walls of thelarge and many of the small crater-like depressions (Fig.
2). Reflectance spectra obtained at German Aerospace
Centre, Berlin, Germany from the frothy material lining
Figure 1. SEM-BSE images of the crater-covered side of A0112 (A) andthe largest crater-like depression are almost featurelessthe largest impact crater surrounded by a spall zone and surface-related,
between 2 and 4 µm (Fig. 3) and resemble those obtained
impact-produced fractures (B).
from the CI chondrite Ivuna heated to 700 °C [13]. Control
spectra obtained from the non-crater-bearing sides of A0112 are consistent with infrared spectra of other Ryugu samples (e.g.,[14]) and showed pronounced spectral features at 2.71 µm and 3.32 and 3.46 µm that correspond to OH-bearing phyllosilicatesand carbonates, respectively. Elemental analysis by energy dispersive X-ray spectroscopy (EDS) and EDS element distribution
maps showed that the frothy materials are quenched silicate–sulfide emulsions, which suggests that the crater-like depressions
and pits are impact craters. Quenched melt splashes up to 300 μm across exist not only on the crater-bearing side of A0112, butalso on an additional side of the sample. These are similar in chemical composition to the frothy layers described recently fromother Ryugu samples [10] and invariably comprise silicate–sulfide emulsions. High-resolution EDS element distribution maps
furthermore suggest that the quenched melts contain immiscible FeNi metal droplets (cf. [11]). In terms of major-element

chemistry,themeltsplashes on A0112 matchfusion crusts around the CI
chondrites Orgueil andAlais [15] and resemble aquenched melt particle oflikely impact-melt origin
Figure 2. SEM-SE image (A) and element distribution map (B) of quenched impact melts lining the bottoms
recently reported fromof the large impact craters on A0112. (C) SEM-BSE image of quenched melt splashes on the surface ofOrgueil [16]. Furthermore,
A0112. A high-magnification element distribution map of the quenched melt splashes is shown in the inset.
μCT scans revealed that thesubsurfaces adjacent to and below the large craters are intensely fractured; in particular, we observed fracture patterns resemblingradial, concentric, and spallation fractures known from impact experiments in the strength regime (e.g., [17] and references
therein). Consistent with lunar microcraters [17], large craters >150 µm are surrounded by irregular spallation zones whereas
small craters <40 µm are almost perfectly bowl-shaped.
While investigations on the impact craters and quenched melts on A0112 are ongoing,
our preliminary results provide information on the nature and magnitude of impactinduced processing of C-type asteroid surfaces in relation to solar wind-induced space
weathering. Sample A0112 appears to be the most intensely shocked Ryugu sample
investigated so far—the majority of smaller Ryugu samples were so far reported to beeither essentially unshocked [18] or only marginally affected by micrometeoroid impacts,with solar wind-derived modifications dominating over impact-induced modifications[10–12]. Our findings of relatively large craters and abundant quenched impact melts on
A0112 suggests that micrometeoroid impacts play an equally important role in space
weathering of C-type asteroid regoliths as solar-wind induced modifications do. Impactinduced fracturing and spallation associated with the large craters on A0112 also informs
on the efficiency of impact-induced fragmentation of grains in C-type asteroid regoliths[19]: Our observations suggest that spallation zones of micrometeoroid impact craters arelikely sources of hydrated carbonaceous micrometeoroids arriving on Earth,contradictory to recent proposals based on unshocked to mildly shocked Ryugu grains[18]. This hypothesis is based on the fact that spall fragments ejected from spall zones
surrounding hypervelocity impact craters are typically unshocked (e.g., [20]), but detailed
numerical models using the iSALE shock physics code are currently being computed toprobe peak pressures and temperatures in the spall zones surrounding the craters on
A0112. If A0112’s microcrater population is representative of Ryugu’s surface, ourresults have relevance for evaluation of the relative roles of thermal [21,22] vs. impacttriggered [17] comminution of, and dust production from, C-type asteroid regolith.
Acknowledgments: We thank JAXA for allocation of Ryugu sample A0112.

Figure 3. Reflectance spectra obtained
from the largest impact crater on A0112(red) compared against a spot far awayfrom the craters (blue). Also shown are
spectra of bulk A particles (green; [14]),
carbonate- and CH-rich spots on
Chamber A particles (light blue; [14]),and heated Ivuna CI chondrite (yellow
and pink; [13]) for comparison.

References[1] Hapke B. 2001. Journal of Geophysical Research Planets 106: 10039–10073. [2] Pieters C. M. and Noble S. K. 2016. Journalof Geophysical Research Planets 121: 1865–1884. [3] Keller L. P. and McKay D. S. 1997. Geochimica et Cosmochimica Acta
64: 2331–2341. [4] Pieters C. M. et al. 2000. Meteoritics & Planetary Science 35: 1101–1107. [5] Noguchi T. et al. 2011. Science
333: 1121–1125. [6] Noguchi T. et al. 2014. Meteoritics & Planetary Science 49: 188–218. [7] Thompson M. S. et al. 2014.
Earth, Planets and Space 66: 89. [8] Yokoyama T. et al. 2023. Science 379: eabn7850. [9] Nakamura T. et al. 2023. Science 379:
eabn8671. [10] Noguchi T. et al. 2023. Nature Astronomy 7: 170–181. [11] Melendez L. E. et al. 2023. Abstract #6286. 86th
Meteoritical Society Meeting. [12] Nakato A. et al. 2023. Earth, Planets and Space 75: 45. [13] Hiroi T. and Pieters C. M. 1996.
Abstract #551. 27th LPSC. [14] Pilorget C. et al. 2022. Nature Astronomy 6: 221–225. [15] Genge M. H. and Grady, M. M. 1999.
Meteoritics & Planetary Science 34: 341–356. [16] Zolensky M. et al. 2022. Meteoritics & Planetary Science 57: 1902–1919.
[17] Hörz F. et al. 2020 Planetary and Space Science 194: 105105. [18] Tomioka N. et al. 2023. Nature Astronomy 7: 669–677.
[19] Flynn, G. J. 2009. Planetary and Space Science 57: 119–126. [20] Melosh H. J. 1984. Icarus 59: 234–260. [21] Delbo M.
et al. 2014. Nature 508: 233–236. [22] Delbo M. et al. 2022 Nature Geoscience 15: 453–457.

Temporal variability of thermal-cycling induced fracturing in chondrites
N. Latsia1, J. Borg1, E. Kaufmann1, M. Granvik1,2 and A. Hagermann11Luleå University of Technology
2
University of Helsinki
Regolith on asteroid surfaces was thought to be a result of micrometeoroid impacts [1], but some recent studies [2,3] claim that
thermal fatigue is the dominant regolith production process on airless bodies. Thermal fatigue is produced by diurnal and/or
annual variations on the surface temperature of asteroids and its efficiency depends on the heliocentric distance, the rotation
period, and the thermal inertia of the asteroid’s surface. A fundamental assumption of previous studies is that thermal fatigue
remains effective over thousands, or even millions, of thermal cycles. However, the Kaiser effect, extensively studied in thefield of fracture mechanics on terrestrial rocks, states that fracturing on materials ceases when previously exerted load levels
are not exceeded [9]. Previous research has demonstrated that the thermal properties of CM2 chondrites depend on theirmineralogy [11]. Thus, the thermal expansion coefficient of each mineral at specific temperature changes can be translated into
different mechanical loads resulting from thermal fatigue.
We aim to observe the time-resolved crack propagation induced by thermal stresses over subsequent thermal load cycles inmeteorites – acting as asteroid analogues – in order to understand the role of thermal fatigue in eroding asteroid surfaces.
According to several studies, Ryugu is similar to CI [5,6,7,8] and CM [8] carbonaceous chondrites, and hence provides groundtruth observations for these samples. We investigate CI, CM, and, for comparison, LL chondrites to examine the behaviour ofthermal fatigue on different petrographic types of meteorites. The samples are subjected to a minimum of 100 cycles at
ΔT=210K as the temperature variation of C-type NEAs is 200K [2]. To identify the spatial occurrence of pre-existing andpropagating cracks, the samples are scanned using X-ray tomography.
We aim to use non-destructive testing (NDT) methods to detect the time and frequency of crack initiation and propagation.
NDT methods are used in many industries to identify and characterize the integrity of a material’s surface and interior without
interfering with its destruction [10]. The Kaiser effect predicts a decrease in the number of produced stresses as the number ofthermal cycles increases, considering that the previous maximum and minimum temperatures of each cycle remain constant at
170Co and -40Co respectively. If the Kaiser effect is applicable, we expect to see the effects of thermal fatigue wane after a few
thermal cycles, suggesting that other mechanisms, such as chemical alteration, are contributing to the breakdown process ofasteroids.
References[1] Housen K.R. et al. 1979. Icarus 39(3) 317-351. [2] Delbo M. et al. 2014. Nature 508(7495) 233-236. [3] Molaro J.L. et al.
2015. JGR Planets 120(2) 255-277. [4] Sakatani N. et al. 2021. Nature Astron 5(8) 766-774. [5] Yokoyama T. et al. 2022.
Science 379(6634) abn7850. [6] Yada et al. 2022. Nature Astron 5(3) 214-220. [7] Kitazato K. et al. 2021. Nature Astron 5(3)246-250. [8] Grott M. et al. 2020. JGR 125(12) e2020JE006519. [9] Kaiser J. 1950. A study of acoustic phenomena in tensile
heat (PhD Thesis). [10] Dwivedi K. S. et al. 2017. Materials Today 5(2) 3690-3698. [11] Opeil C.P. et al. 2020. MAPS 55(8).

CALICO – an ESA M7 proposal to Explore Dwarf Planet Ceres
Axel Hagermann1, Stefan Schröder1 and the CALICO Consortium1Luleå University of Technology
Dwarf planet Ceres was the first member of the asteroid belt to be discovered. It is much richer in water than the other objects
in the asteroid main belt, which suggests an origin elsewhere. Ceres’ surface also shows clear signs of recent, possibly ongoing,
geological activity and is regarded is the closest ocean world to Earth. The ocean worlds of the outer Solar System are of
extreme interest for their potential to support biological activity over geological timescales. Unsurprisingly, the explorationof these enigmatic bodies is one of the priorities of ESA’s Voyage 2050 strategy.
One region on Ceres of particular interest is Occator crater with its bright evaporite deposits, the so-called faculae. Formed by
the extrusion of subsurface liquids, these deposits offer a window into Ceres’ interior. In response to ESA’s call for an M7
mission the international CALICO consortium, led by Luleå University of Technology, proposed CALICO (Ceres
Autonomous Lander Into Crater Occator), a mission that will land in Occator crater and analyse the salt- and organics-rich
deposits of Vinalia Faculae.
CALICO’s science questions cover three themes:
1.
Ceres as an active ocean world2.
Ceres’ potential for habitability
3.
Ceres’ origin and evolution
CALICO will investigate carbon and organic material in the subsurface brine to assess the potential for complex organic
chemistry, it will determine the physicochemical conditions to assess habitability. It will look for the chemical elements
required for the building blocks of life and the elements required for biological energy production.
In order to unravel Ceres’ origin and evolution, CALICO will pay special attention to the role of ammonia in its interior andthe origin of Ceres’ water as well as its magnetic history. CALICO will investigate the links between Ceres, asteroids, comets
and carbonaceous chondrites.
In this talk, the mission concept and science payload of the CALICO mission will be presented, with a brief overview of theevolution and status of the proposal.

Next Generation small body Sample Return mission: a concept study for a future Japanese mission
to a comet
Hiroyuki Kurokawa1, Yuri Shimaki2, Naoya Sakatani2, Ryota Fukai2, Tatsuaki Okada2, Yoko Kebukawa3, Jun Aoki4, Atsushi
Kumamoto5, Taichi Kawamura6, Satoshi Tanaka2, Eri Tatsumi2, Seitaro Urakawa7, Yuichi Tsuda2, Osamu Mori2, Takanao
Saiki2, The Next Generation Small Body Sample Return WG
1
University of Tokyo, 2Japan Aerospace Exploration Agency, 3Tokyo Institute of Technology, 4Osaka University, 5Tohoku
University, 6Université Paris Cité/Institut de Physique du Globe de Paris, CNRS, 7Japan Spaceguard Association

The Next Generation small body Sample Return (NGSR) mission is a future solar-system exploration mission for sample
return from a solar system small body under consideration. In February 2023, we newly launched the Science Working Group(WG) for the NGSR mission. The Science WG studies science goals and mission payloads of the NGSR. In collaboration with
the Engineering WG, the Science WG aims to propose the NGSR as a strategic large-class mission which will be launched in
2030s by ISAS, JAXA. The strategic large-class mission will be selected in late 2024.
The NGSR targets a comet to bring back its subsurface materials and to explore its surface and internal structure. The Science
WG defined the NGSR as a mission to unveil the origin of the solar system, namely, I) the origin of the solar-system“materials” in galactic evolution and II) the origin of the solar-system “bodies” to form planetesimals. For those science goals,
we categorize science objectives as follows: Science objective I-1) unveiling the types of parent stars of the solar-system
materials and their fractions, I-2) elucidating the origins of cometary organic matters, II-1) clarifying whether comets arerubble-pile or a pebble-pile bodies, and II-2) elucidating the formation environment of comets.
Science Goal I can be mainly achieved by sampling and analysis of subsurface materials of the target comet. In contrast to
surficial materials that experienced alteration caused by space weathering and cometary activities, subsurface materials arethought to be pristine record of the original solar-system building blocks and, consequently, of the evolution of materials in ourgalaxy. Excavating and sampling subsurface materials are needed. Moreover, we are planning to install a mass spectrometerfor in situ analysis of volatile materials that will potentially be altered and/or lost before the sample recovery.
Science Goal II can be mainly achieved by physical explorations of the interior structure with a radar and/or seismometer.
Pebble-pile bodies (pristine first-generation of planetesimals) and rubble-pile bodies (disrupted and re-accreted planetesimals)
should have different interior structures; only the latter are thought to possess meter-scale internal voids. The meter-scale
heterogeneity can induce different propagation and reflection patterns for both radio and seismic waves.

Intermediate bodies of Asteroids and the Moon from an Earth 3GMS model
Yasunori MIURA
Department of Earth System Sciences, Faculty of Science, Yamaguchi University

Introduction: Previous formation model of active water planet Earth has been static description of three material states (3MD)from various planetary and Earth sciences, which have been studies in details for more description as public definition fromscientific researched fields to public library and museum for educated words. On the others hands, there are two unsolved itemsof 1) formation of active Earth planet, and 2) formation of inactive Asteroids and the Moon-Mars comparatively in the Earthtype planetary bodies. The main purpose of the paper is to new active Earth formation model called here as Active Three Material
States (A3MS) to be continued to be young products on global and local sites of the planet now [1,2] (Table 1).
Problem and characteristics of the previous 3MD model: The previous 3MD model shows typical merits for the definition ofeach terminology word on educational sites of school, library, book and museum sites, though it shows some demerits for static
description (without previous and future changes in details). This is mainly because planet Earth is not static but so active globallyand locally as complicated phenomena to be changed one direction in wide Universe totally. In fact, we meet difficult spots(totally inactive with old history of primordial ages) to explain the details and comparison of extraterrestrial bodies of many
Asteroids and the Moon and Mars even in neighbor celestial bodied in the Earth-type planetary bodies of the Solar System. We
have to make more detailed figure of active planet Earth from various academic fields of geology, rocky minerals, mixed rocks,
physics-chemistry-biology contently with news sciences of environmental and computer information. It is herewith keeping
unsolved problem for many academic researched fields separated into individual academic fields [3,4].
New model of present S3MS model: It might be difficult to young scientists who study one of many academic fields preciously
for present wide points of academic fields to be explained. However, new wider scientists (even older scientists) fromfundamental Earth sciences (mineral-rock chemistry, micro-observation analyses and wide geological sciences) are possibly
solved totally, where they should be studied also wide planetary fields of planet, physics-chemistry and active shock wave fieldsof quake-volcano-impacts (QVI) processes comparatively [5,6].
Main points of new A3MS model: The present A3MD model shows possible explanation for active process of rocky solid
system of Earth which are activated energy naturally to change rocks from older to newer ages among three material states ofsolid, fluid liquid-to vapor air (SLV), which we can see younger trends of Earth totally. Compared short human life age, the solidof Earth are surely changed with longer times (due to life with light elements from carbon organic molecules with fluid system,compared with rocky system of Earth with longer ages of change comparatively with continued change processes).
Meaning of existences of Atmosphere and Ocean systems on rocks (VLS) to Earth: On primordial period of Earth, naturalactivation energy (QVI) has been started from no ocean system by gravitational quake (tidal) and rocky system to be found threeplanets and the Moon and Asteroids on the Earth-type planetary zone. However present earth site has change to produce, keepin side fluid and solid rock inside as mixture of fluids and vapors for some geological periods to be more active on driedprimordial Earth with huge collisions (i.e. planetary-planetary, and/or multiple asteroids collision, where might be the most big
chance of formation of global ocean mixed fluid system, where characteristic aspects of fluid liquid phases are showing boundaryas image boundaries with irregular round shapes and light molecules with many elements involving between solid (rock) andvapor (air) phases formed as global ocean system on water planet Earth during decreased temperatures and continuous lower
temperature among three material states (VLS) with new formed active phenomena of plate quake and volcano locally to keep
moderate temperature kept in Earth system as moderate complex processes on active Earth now [2-4].
Comparative differences of Earth and other celestial bodies: The present A3MS model can be explained younger planet Earthby natural active phenomena QVI events, which can be shown by major differences between young Earth and other bodies
beyond Earth. The Mineral crystals defined from mall to large sizes with colorful units of Earth can be formed by ocean plate
activities of quake and volcano with interior magmatic melting with irregular but continuous movements under room-temperature
condition of water-Earth, though inactive celestial bodies of Asteroids and the Moon show tiny assemblages of rocks withprimordial ages. Continuous magma melting and metamorphic events are used to be formed final pure and large mineral crystalof quartz SiO2 and CaCO3 calcite carbonates (gem mineral) only water planet Earth. Ocean fluids are water mixed with many
tiny elements from light to heavy metals brought by many asteroid impacts on ocean for longer geological periods, where as insimilar process of mixed rocks to pure mineral crystal the mixed fluid of ocean water can be produces to pure water of rain andunderground water or glacier ice globally as small percentage as pure products on active Earth. Life shows the similar A3MS
assemblages on the rocks of water planet earth corporately as shown in different paper. This suggest comparatively organic life
works can be seen in the complicated and continuous A3MS process discussed in this paper shortly, which it suggests that life
system of organic compounds can be existed and continued the A3MS system on active Earth as we can observed clearly.
Intermediate steps of various Asteroids 1M to the Moon 1M , and Mars 2MS from active planet Earth A3MS: From whole
differences between inactive 1MS (one material state) of Asteroids compared with 2MS (two material states) , the Asteroids
show initial collision aggregates with various grains and rocks of Si-system (mountain rocks), Ca system (ocean rocks) and Fegroup system(heavy iron) with some contents of non-mineral elements of CO(HN)-systems synthesized in organic compounds
on active planet Earth. From active A3MS model, products of non-mineral CHO-system are obtained in continuous and active
planet Earth easily. For inactive Asteroids and the Moon, light element CHO-system groups are easily formed from products
contained carbon elements (cf. steel parts) with impacted sample collections and/or analytical procedures by collision less-shock
wave reactions by electron, ion and laser beam bombardments in analytical cambers are extremely carefully to be interpreted on
the paper [5]. In short, many joined aggregates can be observed in many parts of the Asteroids before forming the Moon or Mars
planet as intermediate solid-aggregated rocks before forming the water planet Earth with other active group of life-A3MS systemgroups [2].

Table.1 Comparison of material states MS of Earth, Asteroid and other extraterrestrial bodies.
Celestial bodies

Mineral or Rocks

Organic Life System

Earth (water planet)

Active three material states (A3MS) system

Non-mineral light elements (CHON) system

Asteroids, the Moon (Mars)

A material state (1MS) Intermediate mixture

Store in solid interior (mixture), Contamination?

Summary: The present work has been summarized as follows.
(1) Active planet model A3MS can be explained on Earth, but others inactive bodies are 3MS on the Solar System.
(2) This model can explain younger rock of Earth and older rocks of other bodies of Asteroids.
(3) New large crystals and life system on Earth and mixed rocks on Asteroids might be explained in the model.
(4) Aggregates observed in the Asteroids before forming the Moon or Mars planet as intermediate solid-aggregated rocks before
forming the water planet Earth with other active groups of life system groups.

References: [1] Miura Y. (2018) IMA-22,1189. [2] Miura Y. (2023) JAMS. E5-15. [3] Wilson J.T. (1965) Nature, 207 (4995),
343-347.

[4] Miura Y. (1996) Shock-Wave Handbook (SV, Tokyo),1073-1209. [5] Miura Y. and Kato T. (1993) AIP, 283, 488-

492. [6] Miura Y. (1992) Celestial Mechanic. & Dynamical Astro. (KA), 54, 249-253.

Chrome-spinel in Hayabusa particles: Recorders of Asteroid Itokawa's thermal history
Jemma Davidson1,2, Devin L. Schrader1,2, Thomas J. Zega3, Pierre Haenecour3, Kenneth J. Domanik3, Kazuhide Nagashima4,
Noriko Kita5 and Philipp Heck6,7.
1
Buseck Center for Meteorite Studies, Arizona State University, AZ 85287, USA
2
School for Earth and Space Exploration, Arizona State University, AZ 85287, USA
3
Lunar and Planetary Laboratory, University of Arizona, AZ 85721, USA
4
Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, HI 96822 USA
5
WiscSIMS, University of Wisconsin-Madison, Madison WI 53706, USA
6
Robert A. Pritzker Center of Meteoritics and Polar Studies, Negaunee Integrative Research Center, Field Museum of Natural
History, Chicago, IL 60605, USA
7
Department of the Geophysical Sciences, University of Chicago, Chicago, IL, USA
Introduction: Chrome-spinel, which includes chromite (FeCr2O4) and Cr-rich spinel ([Mg,Fe][Al,Cr]2O4), records both preand post-accretionary formation conditions while remaining resilient to extensive alteration (e.g., [1–5]). They are found in awide variety of astromaterials, including chondrites, as well as Hayabusa [6] and Stardust [5] returned samples. The
morphologies, chemical compositions, and O-isotope compositions of chrome-spinel minerals in returned samples provide
important information on their primary formation conditions in the nebula (temperature, time, oxygen fugacity) and on thesecondary alteration conditions on the parent body (thermal metamorphism).
Chrome-spinel and olivine in FeO-rich chondrules in carbonaceous and ordinary chondrites are very sensitive indicators ofthermal metamorphism [1,4]. We compare the compositions, textures, and O-isotope compositions of chrome-spinel fromasteroid 25143 Itokawa with those from ordinary chondrites to investigate correlations between formation mechanism, oxygen
fugacity, and formation/alteration temperatures. Studying chrome-spinel in Hayabusa particles constrains the parent bodyformation and alteration conditions of asteroid 25143 Itokawa and provides information about the variety of material present on
this asteroid (e.g., [6]).
Samples and analytical procedures: We were allocated three
Hayabusa-returned particles during the Hayabusa AO7 (Table 1;
Fig. 1a–c). Two of the allocated samples contain olivine-chromespinel pairs, while the third is solely chrome-spinel. All samples arelarge enough for multiple in situ O-isotope analyses.

Table 1. Hayabusa-returned samples for study.
SampleSize (diameter)
PhasesRA-QD02-0316
117 × 51.5 μm
olivine, chr
RB-CV-0091
29.88 × 14 μm
olivine, chr
RB-CV-0262
39.2 × 23.3 μm
chr

Figure 1. Hayabusa particles studied here (a, b, c) before, and(d, e, f) after sample preparation (i.e., mounting in epoxy andmicrotoming). (a–c) Backscattered electron (BSE) images
modified from the JAXA Hayabusa particle catalogue used
for preliminary identification of phases. (d–f) BSE images
showing flat surfaces created by microtoming after mounting
in epoxy. The orientation of RA-QD02-0316 changed slightly
after mounting in epoxy, resulting in a smaller area of
exposed spinel. Where chr = chrome-spinel, ol = olivine, and
FeS = iron sulfide.

Sample preparation: The Itokawa samples were prepared at the University of Arizona's Lunar and Planetary Laboratory (LPL)
following a modified version of the method presented in [7]: the particles were mounted on the top of epoxy bullets, which werethen trimmed and sliced using a Leica EM UC7 ultramicrotome with two diamond knives (a trim knife and a cutting knife) tocreate flat surfaces that were suitable for microbeam analysis. The progressive excavation of each Itokawa grain was monitored
using a Keyence VHX-7000 4K digital-optical microscope at LPL to ensure that overlying epoxy was removed to revealsufficient sample area for further analysis while preserving as much of the particle as possible. Analysis in 3D microscopy mode
confirmed that the microtome method created smooth, flat surfaces ideal for EPMA and in situ O-isotope analysis.
Electron microscopy: The prepared samples were then carbon-coated and imaged in backscattered electron (BSE) mode in a
Hitachi TM4000Plus II Tabletop scanning-electron microscope (SEM) at LPL Kuiper-Arizona Laboratory for Astromaterials
Analysis facility (K-ALFAA) to verify that the microtome method created smooth, flat surfaces required for subsequent
microprobe analysis (Fig. 1d–f). We then determined the major and minor element compositions of olivine and chrome-spinelin each of the Itokawa particles using the Cameca SX-100 EPMA at LPL K-ALFAA.
Results: Olivine-spinel thermometry: The olivine-spinel geothermometer was used to calculate closure temperatures for the two
Itokawa particles that contain olivine and chrome-spinel mineral pairs (RA-QD02-0316 and RB-CV-0091). Quantitative
compositional analyses were performed via EPMA at the edges of mineral pairs to determine the major and minor element
compositions of both phases. Olivine-spinel temperatures were then determined using these data and an Excel version of the
MELTS calculator [9]. Temperatures were determined at a pressure of 1 bar, which is a reasonable approximation for asteroids[10]. These calculations yielded closure temperatures of ~610 ± 50 °C (1 sigma, 1σ) to ~710 ± 50 °C for the different particles,
which agree within a 2σ error. Assuming the olivine and spinel pairs in Itokawa particles originated from chondrules, thesetemperatures do not reflect the conditions of chondrule crystallization but rather closure temperatures after thermal
metamorphism (e.g., [11]), consistent with temperatures recorded by olivine-spinel pairs in LL3.5–6 chondrites [8].
Temperatures indicative of crystallization in the chondrules of LL3.00–3.3 chondrites are typically >1000 °C [8].

Figure 2. Chromite compositions for Hayabusa particles studied
here (H0091, H0262, and H0316; squares) and from [6] (RA-QD020030, -0031, and -0047; diamonds) compared to those from ordinary

Major and minor element compositions: The major andminor element compositions of each of the Itokawa chromespinels show that they have Cr/(Cr+Al) > 0.8, indicating thatthey are all chromite (i.e., FeCr2O4). Their Mg/(Mg+Fe) andAl/(Al+Cr) ratios cover a broader range than chromitecompositions reported from three other Itokawa particles(RA-QD02-0030, -0031, and -0047) [6] (Fig. 2).
Since olivine-spinel geothermometry indicates that the
Itokawa chromites studied here originate from thermally
metamorphosed material, their compositions are comparedwith those from type 4–6 ordinary chondrites (LL, L, and H)(Fig. 2). The Itokawa chromites appear to be slightly lessequilibrated than those previously reported by [6], which
best match LL5 and LL6 chondrites, and cover similar
compositions to chromites from LL4–6 chondrites (seecomparison of OC data from [8] in Fig. 2).

chondrites (fields drawn from data in [6] and [8]).

Discussion: Due to the significant overlap between the major and minor element compositions of chromite from LL4–6
chondrites, it is not possible to match the Itokawa chromites studied here with specific petrologic types. Future work will include
performing in situ O-isotope analyses of both olivine and chrome-spinel phases in each sample. This will enable us to constrain
the specific meteorite petrologic type matches to the Itokawa chromites. However, the presence of Itokawa chromites covering
the same range as LL4–6 chondrites is consistent with Itokawa being a breccia of LL4–6 materials [6].
References: [1] Johnson and Prinz 1991. Geochimica et Cosmochimica Acta 55:893–904. [2] Krot et al. 1993. Earth & Planetary
Science Letters 119:569–584. [3] Kimura et al. 2006. Geochimica et Cosmochimica Acta 70:5634–5650. [4] Davidson et al.
2011. Abstract #5319. Meteoritics & Planetary Science Supplement. [5] Gainsforth et al. 2015. Meteoritics & Planetary Science
50:976–1004. [6] Nakamura et al. 2011. Science 333:1113–1116. [7] Che and Zega 2023. Nature Astronomy
DOI:10.1038/s41550-023-02012-x. [8] Kimura et al. 2006. Geochimica et Cosmochimica Acta 70:5634–5650. [9] Sack andGhiorso 1991. American Mineralogist 76:827–847. [10]. Benedix et al. 2005. Geochimica et Cosmochimica Acta 69:5123–5131.
[11] Wlotzka 2005. Meteoritics & Planetary Science 40:1673–1702.

Coordinated Analyses of Hayabusa particles RB-CV-0234, RB-QD04-0039, and RA-QD02-0310:
Constraints on asteroid Itokawa formation from sulfides and silicates
Devin L. Schrader1 and Thomas J. Zega2
1
Buseck Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, Tempe, AZ 852871404, USA (devin.schrader@asu.edu),
2
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA (tzega@arizona.edu)
Introduction: Sulfides are important phases in planetary materials because their compositions, textures, and crystal
structures can be used to constrain oxygen fugacity of formation, shock stage, and aqueous-, thermal-, and cooling-histories [e.g.,1–8]. The pyrrhotite-group sulfides are largely nonstoichiometric and have a range of compositions (typically 0≤x≤0.125, but x
can be ≤0.2; i.e., FeS [troilite] to Fe0.8S) and distinct crystal structures (polytypes). The stoichiometric end members are 2C(troilite; FeS, hexagonal) and typically 4C (Fe7S8, monoclinic) pyrrhotite. There are also pyrrhotites of intermediate compositions
with 0≤x≤0.2 (all hexagonal), including the non-integral NC-pyrrhotites and the integral 5C (Fe9S10), 6C (Fe11S12), and 11C(Fe10S11) pyrrhotites [e.g., 9–11]. Geothermometry of pyrrhotite-pentlandite intergrowths in meteorites shows that most formed
via primary cooling from high temperature (i.e., chondrule cooling in the protoplanetary disk) or thermal alteration on the parent
body [e.g., 12–14]. Sulfides in the LL4 to LL6 chondrites typically equilibrated ≤230°C, consistent with formation during coolingafter thermal metamorphism [2]. Analyses of Hayabusa particles identified asteroid 25143 Itokawa as LL4–6 chondrite material(~10% LL4 and ~90% LL5–6) [e.g., 15–18] that was thermally metamorphosed between ~780 and 840°C [15]. Itokawa particles
were found to record shock stages between S2 and S4, with most particles around S2 [19,20]. Sulfides in Hayabusa particles[e.g., 15,21,22] may record additional and/or complementary information on theformation conditions of asteroid Itokawa.
We performed coordinated analyses of the Hayabusa particles RB-CV-0234,
RB-QD04-0039, and RA-QD02-0310, allocated in Hayabusa AO5. Preliminary
analysis by JAXA’s Hayabusa examination team via scanning electron
microscopy (SEM) determined that particle RB-CV-0234 (25.9 μm in diameter)
consists of FeS, Fe, FeNiS, and CuS, making it an ideal target potentiallycontaining both pyrrhotite group sulfides [(Fe,Ni,Co,Cr)1– xS] and the rare Ni-richsulfide, pentlandite [(Fe,Ni,Co,Cr)9S8]. In addition, JAXA’s Hayabusa
examination team determined that particle RB-QD04-0039 (52 μm in diameter)
consists of olivine, low-calcium pyroxene, and troilite, and that particle RAQD02-0310 (127 μm in diameter) consists of olivine, plagioclase, and troilite.
These two Hayabusa particles provided excellent opportunities to identify
Figure 1. Composite TEM X-ray element map(RGB=FeSNi) of RB-CV-0234 FIB Section;
sulfides with petrographic context and to analyze their adjoining silicate
where po = pyrrhotite and pn = pentlandite.
minerals, unlike RB-CV-0234 that only contained sulfides. Here, we comparedin situ analyses of these particles to the results from LL3–6 chondrite silicates and sulfides [e.g., 1,2], with the goal of further
constraining the formation and alteration conditions of asteroid Itokawa. Preliminary analyses from RB-CV-0234 and RB-QD040039 were presented in [23,24,25].
Samples and Analytical Procedures: We mounted RB-CV-0234, RB-QD04-0039, and RA-QD02-0310 each on epoxy
bullets, using a method modified from [21], and microtomed them in preparation for analysis and sample extraction using the
FEI Helios NanoLab 660 focused-ion-beam-SEM (FIB-SEM) at the University of Arizona (UAz). X-ray element maps and highresolution images of the microtomed RB-CV-0234 and RB-QD04-0039 were obtained with the FIB-SEM prior to extraction ofa ~10 × 10 μm sections from each particle, which were then thinned to electron transparency (<100 nm) following the methodsof [26]. The FIB sections were then analyzed using the 200 keV aberration-corrected Hitachi HF5000 scanning transmission
electron microscope (S/TEM) at UAz. After a FIB section of the sulfide from RB-QD04-0039 was obtained, RB-QD04-0039
was analyzed on the Cameca SX-100 electron microprobe (EPMA) at UAz. Microtome preparation of RA-QD02-0310 did notreveal sulfides for further structural analyses via TEM, but the compositions of its silicates were determined via EPMA at UAz.
Results: FIB-SEM X-ray element maps showed that the microtomed surface of RB-CV-0234 consisted entirely of pyrrhotite.
However, X-ray element maps of the extracted FIB section, determined via TEM analysis, revealed a single large grain of
pyrrhotite and a single smaller grain of pentlandite (4.8 × 1.3 μm) at the bottom of the section (Fig. 1). Selected-area electrondiffraction (SAED) patterns of the pyrrhotite and pentlandite grains index to 2C pyrrhotite (troilite) and pentlandite along the[110] zone axis (i.e., they are crystographically oriented), respectively. The compositions of RB-CV-0234 via quantitative

energy-dispersive X-ray spectroscopy [27] are 35.2 wt.% S and 64.8 wt.% Fe for pyrrhotite, and 32.4 wt.% S, 49.4 wt.% Fe, and18.2 wt.% Ni for pentlandite. The microtomed surface of RB-QD04-0039 showed a single sulfide grain, as well as olivine(Fa28.1–29.5, Fa28.9±0.5 [1σ]; n = 7) and low-calcium pyroxene (Fs23.8–24.9, Fs24.3±0.6, Wo1.1±0.1 [1σ]; n = 3) (Fig. 2). A
FIB section of the sulfide grain in RB-QD04-0039 revealed it to be troilite. The microtomed surface of RA-QD02-0310 showeda grain of olivine (Fa28.9–31.3, Fa30.2±0.8 [1σ]; n = 12), with two chrome-spinels.
Discussion: The sulfides in RB-CV-0234 are most consistent with it being
a sulfide grain from an LL6 chondrite, similar to the sulfides from Saint-Séverin
studied by [1,2]. We infer this because: (1) the Ni content of pentlandite isconsistent with the characteristic Ni contents of LL chondrite pentlandite [2,14];and (2) based on results from the LL3–6 chondrite sulfides we previously
studied [1,2,14], sulfide grains in Saint-Séverin (LL6, S2 [2,28]) contain asimilar pentlandite/pyrrhotite morphology (i.e., blocky pentlandite inpyrrhotite) and 2C pyrrhotite (troilite) with pentlandite [1]. The other LL
chondrites we studied contained either a distinct morphology (e.g., pentlandite
lamellae) and/or multiple polytypes of pyrrhotite [1,2]. The compositions ofpyrrhotite and pentlandite in RB-CV-0234 are consistent with equilibrating<300°C, perhaps as low as 230°C, similar to that of LL4–6 chondrites [2,25].
The olivine grain in RB-QD04-0039 contains planar fractures, indicating a
shock stage of at least S3 and minimum shock pressures of 5–10 GPa [29]. The
silicate compositions of both RB-QD04-0039 and RA-QD02-0310 (Fa28.9±0.5
and Fa30.2±0.8, respectively) are consistent with that of equilibrated LL
chondrites, consistent with that found by [15] for Hayabusa particles. Relative
to the iron-wüstite (IW) buffer, the oxygen fugacity constraints on the formationof troilite [30] and of pentlandite [14] indicates that RB-CV-0234 and RBQD04-0039 were likely altered between approximately IW–2.2 and IW,
consistent with that found for LL5 and LL6 chondrites by [14]. Therefore, theFigure 2. (a) Back scattered electron (BSE)
morphology and chemical compositions of sulfides and silicates of RB-CVimage and composite EPMA X-ray element map(RGB=FeMgSi) of RB-QD04-0039; LCP =0234, RB-QD04-0039, and RA-QD02-0310, as well as inferred sulfide
low-calcium pyroxene.
equilibration temperature and oxygen fugacity constraints are consistent withequilibrated LL chondrites.
Acknowledgements: We thank JAXA for the loan of the Hayabusa particles used in this study through the 5th International
Announcement of Opportunity, and NASA grant NNX17AE53G (DLS PI, TJZ Co-I) for funding this research.
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System Materials. [24] Schrader D. L. and Zega T. J. 2019a. Lunar Planet. Sci. L, Lunar Planet. Inst., Houston, #2009. [25]Schrader D. L. and Zega T. J. 2019b. Abstract #6400. 82nd MetSoc. [26] Zega T. J. et al. 2007. Meteorit. Planet. Sci. 42:1373.
[27] Zega T. J. et al. 2018. Abstract #2084. Microsc. Microanal. 24 (Suppl. 1). [28] Rubin A. E. 2004. Geochim. Cosmochim.
Acta 68:673. [29] Stöffler D. et al. 2018. Meteorit. Planet. Sci. 53:5. [30] Schrader D. L. et al. 2021. Geochim. Cosmochim. Acta
303:66.

Are there 100s of ppm water in nominally anhydrous minerals of non-carbonaceous asteroids?
Dennis Harries1
European Space Resources Innovation Centre (ESRIC), Luxembourg Institute of Science and Technology, 41 rue du Brill, L4422 Belvaux, Luxembourg1

Non-carbonaceous (NC) asteroids of mainly the S type comprise a large fraction of objects in the main asteroid belt and among
the near-Earth asteroid population. Materials represented by them have played significant roles in the accretion of theterrestrial planets, but generally NC materials have been considered essentially dry relative to carbonaceous chondrites (CC).
In consequence, NC planetesimals were usually not considered as carriers of H2O delivered to the early Earth. Recently, SIMS
studies of regolith particles returned by JAXA’s Hayabusa mission from S-type/LL-group asteroid 25143 Itokawa havereported 240 to 990 ppm H2O in the nominally anhydrous minerals (NAMs) orthopyroxene, olivine, and albite [1,2].
Additional data has indicated similar contents in NAMs of equilibrated chondrites of the L and LL groups [1,3] and in NAMsof unequilibrated chondrites [4].
H2O contents on the order of 100s of ppm in NAMs of ordinary chondrites would have substantial implications for the earlyaccretion of H2O to the proto-Earth and would also imply high lithostatic pressures during thermometamorphism withinchondritic planetesimals not consistent with current size estimates. Moreover, high water-to-rock ratios during metamorphism
could indicate much higher bulk H2O contents of pristine equilibrated chondrites beyond the defect-bound hydroxyl
component, e.g., in the form of fluid inclusions. This would have considerable implications for the targeting of S-type nearEarth asteroids for in-situ space resources utilization (ISRU).
In order to shed more light on the H2O contents in asteroidal NAMs, we have conducted a survey of H2O in equilibratedchondrites and achondrites using the NanoSIMS 50L at the Open University, UK [5]. This contribution serves to place theseresults in perspective with other recent findings. The NAMs studied comprise olivine and orthopyroxene from a set of
equilibrated ordinary chondrites of the L and LL groups (Baszkówka, Bensour, Kheneg Ljouâd, and Tuxtuac) and several
ultramafic achondrites (Zakłodzie, Dhofar 125, Northwest Africa [NWA] 4969, NWA 6693, and NWA 7317). For calibration
we used terrestrial olivine and orthopyroxene with H2O contents determined by Fourier transform infrared spectroscopy. Our
99.7% (~3SD) detection limits achieved were 3.6 to 5.4 ppm H2O for olivine and 7.7 to 10.9 ppm H2O for orthopyroxene.
Our survey did not identify any meteorite sample that consistently showed H2O contents in NAMs above our detection limits.
Other recent SIMS studies of H2O in NAMs of ungrouped achondrites and acapulcoites/lodranites, including NWA 6704
(paired with our sample of NWA 6693) and Dhofar 125, did not detect H2O above 2.1 ppm [6] and 6.6 ppm [7], respectively.
SIMS analyses of NAMs in unequilibrated chondrites by have also indicated very low H2O contents of 8 to 14 ppm in thesematerials [8].
Finding H2O contents one to two orders of magnitude lower than previously reported suggests that the parent planetesimals of
the highly metamorphic chondrites, primitive achondrites and ultramafic achondrites studied were efficiently degassed duringmetamorphism and melting, if they initially had held substantial amounts of volatiles [5,6]. The discrepancies between SIMS
analyses of Itokawa samples/equilibrated chondrites showing 100s of ppm H2O on the one hand and equilibrated chondrites
showing hardly any detectable H2O on the other hand may stem from two contributions: Systematic errors of the analyses
and/or heterogeneity of the samples. Sample contamination leading to systematically biased H2O contents is a major suspect. It
appears more likely to occur than H2O loss from the strongly bound hydroxyl defects in NAMs, which requires substantial or
prolonged heating to diffusively remove H2O. The studies available rarely analysed the same samples or meteorites, rendering
it difficult to rule out sample heterogeneity. However, there is currently no other indication to support the hypothesis that
common equilibrated chondrites underwent metamorphism under vastly different peak pressures and H2O fugacities, leading toheterogeneous H2O contents in NAMs among different meteorites.
Hence, the presence of 100s of ppm H2O in samples of asteroid Itokawa and equilibrated non-carbonaceous chondrites isdoubtful and the role of their parent bodies in delivering water to the terrestrial planets needs to be questioned.
References[1] Jin Z. and Bose M. 2019. Science Advances 5:eaav8106. [2] Chan Q.H.S. et al. 2021. Scientific Reports 11:5125. [3] Jin Z.
et al. 2021. Planetary Science Journal 2:244. [4] Stephant A. et al. 2017. Geochimica et Cosmochimica Acta 199:75–90. [5]Harries D. et al. 2023. Meteoritics & Planetary Science 58:705–721. [6] Newcombe M.E. et al. 2023. Nature 615:854–857. [7]Stephant A. et al. 2023. Earth and Planetary Science Letters 615:118202. [8] Shimizu K. et al. 2021. Geochimica et
Cosmochimica Acta 301:230-258.

Development of Nondestructive X-ray CT Imaging Techniques to Identify and Locate Presolar
Grains in Meteorite Sample Jbilet with Application to Ryugu Samples
D. Z. Shulaker1, M. Ferrucci2, B. M. Rogers2, M. R. Savina1, B. H. Isselhardt1, Q. Shollenberger1
1
Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, CA (shulaker1@llnl.gov)
2
Materials Engineering Division, Lawrence Livermore National Laboratory, CA.
Introduction: The development of non-destructive analytical methods of precious material from sample-return missions isnecessary to preserve as much material as possible, including presolar grains. Most commonly, an entire sample is dissolved toisolate presolar grains from the sample matrix. However, dissolving an entire meteorite or material from a sample-return
mission also dissolves essentially everything but presolar SiC, graphite, and nanodiamonds. This results in the loss of precious
material and presolar silicates. In attempt to save sample material, previous studies target presolar graphite and silicon carbide(SiC) grains using nanoscale secondary ion mass spectrometry (NanoSIMS), scanning electron microscopy (SEM), and/or
focused ion beam (FIB) to image regions of meteorite fragments or thin sections [1–6]. When compared to traditional
dissolution of meteorite fragments, these methods preserve grains and contextural information. However, these methods are
exceptionally time consuming, cover very little sample surface area, and often result in locating few presolar grains.
X-ray computed tomography (CT) is a non-destructive imaging technique that generates a three-dimensional
representation of a sample in terms of an X-ray attenuation image. X-ray CT is used extensively in many fields of research andin industry, though its application to locating and identifying graphite and SiC grains in meteorites and other precious samples
from sample-return missions is limited. X-ray CT is promising for this task because of its potential to locate and identify 10s to
100s of presolar grains while preserving the sample. The X-ray CT images can also be used to efficiently target specificregions in the sample for more precise characterization by NanoSIMS or for subsequent analyses, such as by resonanceionization mass spectrometry (RIMS). In this work, we present ongoing work in the development of an X-ray CT based
paradigm for imaging fragments of meteorite sample Jbilet Winselwan (hereafter referred to as Jbilet) to locate and identify
presolar grain types. Ultimately, X-ray CT will be used to image Ryugu fragments to locate and identify presolar grains andplace presolar grains in mineralogical context. The X-ray CT image of the full Ryugu fragment will be used to intelligently
target smaller regions of interest for subsequent isotopic analyses by NanoSIMS and RIMS.
Methods: To develop X-ray CT imaging techniques, a ~150 μm diameter fragment of Jbilet was mounted on carbon tape on
an SEM stub. This was imaged on a Zeiss Xradia 510 Versa using a conventional acquisition and subsequent tomographic
reconstruction by cone-beam filtered back projection. The reconstructed image consists of a three-dimensional array ofvolumetric picture elements (voxels), each assigned a gray value corresponding to the attenuation of X-rays by the material(s)contained within the voxel. The ability to distinguish features in the sample is dependent on the ability to detect changes in thereconstructed gray values. X-ray attenuation is a function of material composition (namely, atomic number, and physicaldensity) and photon energy. Conventional cabinet X-ray systems typically use vacuum tube X-ray sources, which generate
polychromatic ‘bremsstrahlung’ X-rays, i.e., characterized by a broad range of photon energies. However, since conventional
reconstruction algorithms assume monochromatic X-rays, changes in the reconstructed gray values are not linearly related tochanges in atomic number and/or physical density. The absence of sensitivity to photon energy in conventional X-ray CT
imaging means that it is difficult to distinguish features with similar material properties, such as presolar grains.
One of our long-term objectives is to perform multi-spectrum acquisitions for direct material characterization byleveraging so-called ‘dual-energy’ acquisitions: two datasets acquired under distinct X-ray spectra, and a home-grownalgorithm for decomposing the acquired data into voxel-wise effective atomic number and electron density [7]. As a precursor
to our long-term objective, in this study we performed a conventional ‘single-spectrum’ acquisition at 40 kV tube acceleration
voltage with a voxel size of 240 nm (Fig. 1). The reconstructed image was subsequently analyzed with VGStudio (Volume
Graphics GmbH) and its foam/powder analysis functionality to identify individual particles and to extract their morphologicaland gray value statistics.
Results: Despite the previous caveat on relating gray value changes to material differences, features with substantiallydifferent attenuation properties could be distinguished using the mean gray value of the voxels contained within the particle
regions. Furthermore, we can compare the extracted particle morphology, such as sphericity, diameter, and volume, to
expected morphology for each grain as an additional criterion for particle classification. Based on these criteria, we make thefollowing observations: (1) pores are typically less than 15 μm in diameter; (2) larger spherical voids approximately 20 μm indiameter are surrounded by purportedly concentric shells of high attenuation particles with a finer particle size compared to thematrix, and (3) particles with the highest mean attenuation values are highly spherical and generally less than 5 μm in diameter.
Using the data collected in this study in concert with previous studies of Jbilet [8,9], we hypothesize the identification ofvarious discrete particles. For instance, that the larger, spherical features could be chondrules or chondrules with alteration
phases and smaller high mean grey value spherical particles could be metal blebs.
Future work: We have identified several ways to overcome identified limitations with X-ray CT, such as reducing imaging
artifacts, improving image quality, and spatial and attenuation resolution. For instance, without energy sensitivity in theacquisition and subsequent reconstruction, it is difficult to separate grains with similar morphology but distinct material
properties, like SiC and graphite. Beam-hardening artifacts (such as false high gray value regions due in large part to theabsence of energy sensitivity observed at the exterior edge of the meteorite as shown in Fig. 2) can interfere with the correct
identification of features. By imaging a thinner fragment, we can use lower energy photons, which will result in reduced beamhardening artifacts and increased sensitivity to small changes in material properties within the sample.
We will also investigate the inclusion of external material references, such as synthetic SiC and graphite, into themeasurement volume to serve as gray value benchmarks for identifying the same materials inside the sample.
Acknowledgments: We thank G. Brennecka for the Jbilet Winselwan meteorite sample and A. Mohan for reconstruction
assistance. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National
Laboratory under Contract DE-DEAC52-07NA27344 and was supported by the Laboratory Directed Research andDevelopment Program at LLNL under project 20-ERD-030 and 23-LW-015. LLNL-ABS-854399.
References: [1] Nguyen A. N. et al. (2007) ApJ, 656, 1223–1249. [2] Keller L. et al. (2012) MicroSC, 18, 1704–1705. [3]Davidson J. et al. (2014) GCA, 139, 248–266. [4] Sanghani M. N. et al. (2021) ApJS, 352, 1–26. [5] Barosch J. et al. (2022)
ApJL, 935, 1–12. [6] Nguyen A. N. et al. (2023) Sci. Adv., 9, eadh1003. [7] Azevedo S. G. et al. (2016) IEEE Trans Nucl Sci,
63, 341–350. [8] Friend P. et al. (2018) Meteorit. Planet. Sci., 53, 2470–2491. [9] King A. J. et al. Meteorit. Planet. Sci., 54,
521–543.

Figure 1. X-ray CT image of a ~150 μm diameter

Figure 2. Cross section slice through a reconstructed

Jbilet fragment.

X-ray CT image of Jbilet fragment. Examples of observed
characteristics: square is a pore, triangle is metal bleb, and thecircle is a chondrule. Arrows point to the “beam hardening”
artifact that appears around the meteorite edge.

X-ray nano-CT and TEM-EDS Analyses of Impact Melt Splashes on Ryugu Samples
Megumi Matsumoto1*, Junya Matsuno2, Akira Tsuchiyama2,3, Tomoki Nakamura1, Yuma Enokido1, Masahiro Yasutake4,
Kentaro Uesugi4, Akihisa Takeuchi4, Satomi Enju5, Shota Okumura6, Itaru Mitsukawa6, Mingqi Sun3, Akira Miyake6,
and the Hayabusa2 initial analysis team.
1

Department of Earth Sciences, Tohoku University, Tohoku University, Miyagi 980-8578, Japan. 2Research Organization of
Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan. 3Chinese Academy of Sciences (CAS) Key
Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials,
Guangzhou Institute of Geochemistry, CAS, Guangzhou 510640, China. 4Japan Synchrotron Radiation Research Institute(JASRI), SPring-8, Hyogo 679-5148, Japan. 5Earth’s Evolution and Environment Course, Department of Mathematics,
Physics, and Earth Science, Ehime University, Ehime 790-8577, Japan. 6Division of Earth and Planetary Sciences, Kyoto
University, Kyoto 606-8502, Japan.

Introduction: Ryugu samples are chemically and mineralogically similar to CI chondrites, and consist mainly of Mg-rich
phyllosilicates, Fe-Ni-sulfides, magnetite, carbonates, hydroxyapatite, organic matters, and other minor minerals [1–5]. Some
Ryugu particles experienced space weathering on the asteroid surface and exhibit amorphized and melted sample surfaces formedby solar wind irradiation and micrometeoroid bombardments [6]. A0067 and A0094 particles are among the space weathered
Ryugu samples [6] and have flat sample surfaces which exhibit a lot of microcraters and impact melt splashes. In the present
study, we investigated one relatively large microcrater (A0067-crater#1) and two impact melt splashes (A0067-melt#1 andA0094-melt#1) on the two particles (Fig. 1) by scanning electron microscope equipped with energy dispersive X-ray
spectroscopy (SEM-EDS), X-ray nano-tomography (XnCT), and scanning transmission electron microscope (STEM) equippedwith EDS to unveil the nature of the impactors hit on the asteroid Ryugu.
Results and Discussion: A0067-melt#1 shows round shape (~20 µm in diameter) and is composed of a Mg-Fe-rich glassy
silicate main body and an Fe-rich opaque drop (~10 µm) attaching on the glassy silicate. It was extracted from the A0067 particle
using focused ion beam technique and analyzed by XnCT and STEM-EDS. The analyses revealed that A0067-melt#1 is attached
onto the saponite-rich coarse phyllosilicate layer (~1–4 µm in thickness) [2] developed
along with the A0067 main body surface. Some gaps occur between the phyllosilicate
sheets. These probably formed from shrinking of the phyllosilicate layers associatedwith volatile losses caused by the attaching of the hot impact melt splash. The glassy
silicate in A0067-melt#1 has homogeneous Mg-Fe-rich composition with the ratio
Mg/(Mg+Fe) in atom (hereafter Mg#) of ~0.64 and contains only small amounts of
Fe-Ni metal–sulfide spherules (<100 nm). The Fe-rich opaque drop consists ofdendritic crystals of α-(Fe-Ni) (~200–300 nm) embedded in the matrix composed
mainly of troilite and minor pentlandite, and probably formed by a rapid cooling of an
Fe-S-Ni melt.
A0094-melt#1 shows hourglass-like morphology (~15 × 5 µm) and is probably
made of two Mg-Fe-rich glassy silicate drops connected to each other. XnCT–STEMEDS analyses revealed that A0094-melt#1 is compositionally inhomogeneous andshows patchy structure with Fe-rich (Mg# 0.52–0.55) and Fe-poor (Mg#~0.79) glassy
silicate regions (2–5 µm in size). The boundaries between the regions are unclear.
Spherical voids (a few tens of nanometers to ~2 µm) are abundant both in the Fe-richand the Fe-poor regions. The Fe-poor region contains almost no crystalline phase
whereas the Fe-rich region contains spherical and irregular-shaped Fe-Ni sulfides(<500 nm) and olivine grains (1–2 µm). Some aggregates (0.3–1 µm) consisting
mainly of spongy inorganic carbon, irregular-shaped Fe-Ni sulfides, and Mg-richsilicates were also observed in A0094-melt#1. The aggregates are textually similar toprimitive organic materials reported in anhydrous chondritic IDPs and carbonaceouschondrites [7], and might have formed from such primitive organic matters throughvolatile losses caused by impact induced heating.
Fig. 1. FE-SEM images of A0067melt#1, A0094-melt#1, and A0067A0067-crater#1 is ~5 µm in diameter. XnCT–STEM-EDS analysis revealed thatcrater#1.
A0067-crater#1 is ~4 µm in depth and traps small amount of mixture of glassy silicate

and troilite. The mixture should be an impact melt and shows flow structure consisting of glassy silicate and troilite layers (30–250 nm in thickness) stacking with each other. The glassy silicate layer is compositionally inhomogeneous and separated into
Si-poor and Si-rich glasses. Both the silicate glasses contain spherical voids (<200 nm) and Fe-Ni sulfide spherules (<100 nm).
The Si-poor glass (Mg#~0.72) is abundant compared to the Si-rich glass and compositionally similar to the glassy silicates in
A0067-melt#1 and A0094-melt#1. The Si-rich glass selectively occurs along with the crater wall and probably formed in-situ
from a Si-rich source material originally distributed on the A0067 particle surface. In the present study, we observed thin (<100nm) Si-rich layers on A0067 and A0094 particle surfaces. These might correspond to the Si-rich vaper deposits previously
reported on surfaces of some space weathered Ryugu particles [6] and may be the source of Si-rich glass in A0067-crater#1.
In the impact melts, different source materials such as impactors and Ryugu surface materials would have been mixed. The
impact melts studied consist mainly of Mg-Fe-rich glassy silicate parts whose major element compositions (including Fe-Ni
sulfide and olivine grains) are plotted along with an extension of a line connecting the CI (solar) composition [8] and the Fevertex in a (Si+Al)–Mg–Fe ternary diagram (Fig. 2). This suggests the impact melts studied have common source materials andthe compositional trend seems to represent a mixing line of the source materials. A0094-melt#1 shows compositional
inhomogeneity suggesting an incomplete mixing of the source materials, and the Fe-poor and the Fe-rich regions might beproximate to the original source materials. The Fe-poor region is compositionally similar to the Mg-rich phyllosilicate matrix in
the Ryugu samples (Fig. 2) [2] , which consists >80 vol.% of Ryugu samples, and probably sourced from Ryugu surface materials.
On the other hand, the Fe-rich region has CI-like composition which deviate from the compositions of Ryugu’s phyllosilicatesand other Ryugu components (Fig. 2). This suggests that Ryugu is not the source of the Fe-rich region and that the Fe-rich region
was probably sourced from the impactors. The known small planetary materials having CI-like compositions are interplanetary
dust particles (IDPs) and micrometeorites derived from asteroids and comets. Among those, anhydrous chondritic IDPs havebulk compositions which match well with the compositional range of the impact melts studied (Fig. 2) [9], and might be thesource of the Fe-rich region. This is consistent with the presence of the carbonaceous aggregates, which might have formed fromprimitive organic matters, in A0094-melt#1. These mean that the impact melts studied might have formed by anhydrous
chondritic-IDPs impacts on the Ryugu’s surface. Further study of many more impact melt splashes and microcraters will giveimportant information about the variation and flux of the impactors that hit on asteroid Ryugu.

Fig. 2. (Si+Al)–Mg–Fe atom% ternary diagram of compositions of the melt splashes. (A) The major element compositionsof the melt splashes studied and (B) those of IDPs. The compositions of IDPs are from [9], Ryugu’s bulk composition is from[1], and the composition of the phyllosilicates in the Ryugu samples is from [2]. The compositional field of Ryugu
phyllosilicates (774 analyses) [2] is shown as a green colored oval.
Reference: [1] Yokoyama et al. (2023) Science, 379, eabn7850. [2] Nakamura et al. (2023) Science, 379, eabn8671. [3] Ito etal. (2022), Nat. Astron. 6, 1163–1171. [4] Nakamura et al. (2022) Proc. Jpn. Acad. Ser. B 98:227. [5] Yamaguchi et al. (2023),
Nat. Astron. 7, 398–405. [6] Noguchi et al. (2023) Nat. Astron. 7, 170–181. [7] Matrajt et al. (2012) Meteorit. Planet. Sci. 47,
525–549. [8] Lodders (2021) Space Sci. Rev. 217, 44. [9] Schramm et al. (1989) Meteoritics 24, 99–112.

Comparison of Thermal Diffusivity between Ryugu grains and Carbonaceous Chondrites
Takuya Ishizaki1, Ryota Fukai1, Rei Kanemaru1, Keisuke Onodera2, Yoshinao Yasuda3,
Toru Yada1, Masanao Abe1, Tatsuaki Okada1, Tomohiro Usui1
1
Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210, Japan
2
The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
3
Kwansei Gakuin University, 1-155 Uegahara Ichiban-cho, Nishinomiya, Hyogo 662-8501, Japan

Introduction: According to the general planetary formation scenario, the Solar System bodies evolved over a long period oftime through repeated collision, fragmentation, and aggregation of planetesimals formed in the solar nebula. Thermal evolution,
which induces various physicochemical reactions such as aqueous alteration, thermal metamorphism, and volcanism, is important for the evolution of planets. The temperature history inside the planetesimals followed in thermal evolution can vary
greatly depending on when and how large they agglomerate and their effective thermal conductivity. Therefore, it is essential
for the theory of planetary system formation to know the thermal conductivity of asteroids and meteorites, especially those thatare thought to have existed since the early stages of planetary system formation.
The Ryugu sample brought back in 2020 by Hayabusa2 was found to be a primitive Ivuna-type carbonaceous chondrite, which
is close to the average chemical composition of the Solar System [1]. Additionally, the elastic properties of the Ryugu grains
were found to be similar to those of the Tagish Lake meteorite [2]. On the other hand, the thermophysical properties of Ryugu
grains were found to vary widely from grain to grain [3]. Although this is the most important parameter in understanding thethermal history of asteroidal parent bodies, the cause of this variation has not been clarified. In this study, we measured thethermal diffusivities of Ryugu particles and carbonaceous chondrites using the lock-in thermography (LIT) periodic heating
method [3], which was also used for the initial analysis of Ryugu grains to evaluate how the thermal properties of Ryugu grains
are related to those of other carbonaceous chondrites.
Samples and Methodology: In this study, the thermal diffusivities of Ryugu and the carbonaceous chondrites were measured.
A breakdown of the samples is as follows: three grains of Ryugu (A0172, A0038, and C0054), three grains of Ivuna (CI), one
grain of Murchison (CM2), one grain of Tarda (C2-ungrouped), three grains of Tagish Lake (C2-ungrouped), and two grains ofAllende (CV3). Bulk densities of the sample were also measured by obtaining weights and volumes of the sample. The volume
was obtained by using an X-ray computed tomography (X-CT) device (SKYSCAN 1272). The X-CT images were also utilized
to avoid cracks inside the sample, because the cracks may specifically affect to the results of the thermal diffusivity measurements.
In the measurement by the LIT periodic heating method, a spot on the sample is periodically heated using a laser, and thetemperature response is measured by LIT to obtain the phase lag distribution on the sample surface. Then, the thermal diffusivity
is analyzed from the gradient of the phase lag according to this equation;. Here, D is thermal diffusivity, f isheating frequency, θ is phase lag and r is distance from heating point. A measurement apparatus was originally constructed by
combining a LIT (InfraTec ImageIR® 8350hp) with InSb cooled detector and 3x objective lens which provides a spatial resolution of 5 μm, optics, and a diode laser (633 nm, less than 10 μm of focus diameter). The laser beam was modulated according to
the synchronized periodic signal from LIT, and an average power was estimated to be less than 10 mW. The schematic of themeasurement is shown in Figure 1.

Figure 1 Schematic of the measurement.

The heating frequency was selected according to the sample size to avoid the influence of reflected temperature waves at the
sample edge, and then measurements were performed at 20 Hz. The samples were measured under vacuum conditions of apressure less than 10−4 Pa to refrain the effect of the surrounding air because the air causes the overestimate of the thermal
diffusivity in the case of the low thermal diffusivity material.

Results and Discussion: The average value of the measured directional distribution of the thermal diffusivities of the Ryugu
grains were (1.5−3.7) × 10−7 m2/s. The thermal diffusivity of A0308 was particularly low, averaging 1.5 × 10−7 m2/s, which is
the lowest value among all the Ryugu grains ever measured. The thermal diffusivities of the ten grains of carbonaceous chondrites were (1.5−5.1) × 10−7 m2/s, with the Allende meteorite having a definitely higher value and the Tagish Lake meteorite
having a definitely lower value than that of the others. The results for the other meteorites coincided within the margin of error.
Figure 2 shows the relationship of the thermal diffusivity and bulk density for each sample. Figure 1 also includes the resultsof the initial analysis of Ryugu [3], and reference values of Allende (CV3) measured by Soini et al. [4], and Murchison (CM2),
Murray (CM2), Cold Bokkeveld (CM2), Jbilet Winselwan (CM2) and NWA 7309 (CM2) by Opeil et al. [5] are also shown as
square plots. The results show a positive correlation between thermal diffusivity and bulk density, which is in agreement withreference values, except for Jbilet Winselwan and NWA 7309. Tagish Lake and Ryugu have the smallest thermal diffusivity anddensity among the groups that experienced the aqueous alteration, including Ryugu. On the other hand, the density and thermal
diffusivity of Allende are confidentially larger than the other carbonaceous chondrites and Ryugu. There are several possible
causes explaining the variation: (i) thermal diffusivities and densities of Ca- and Al-rich inclusions and chondrules are possibly
larger than those of the matrix and Allende has a larger volume fraction of them [6]; (ii) the thermal diffusivity of the matrix
possibly to be larger when olivine content is higher; (iii) the thermal diffusivity may be reduced by pores and cracks in the matrix
developed during an aqueous alteration. We still have no clear conclusion for the cause of variation. Nevertheless, the variationof the thermal diffusivity and relationship with the density is critical for the thermal evolution of the planetesimals.
Also, Ryugu grains show a thermal diffusivity-bulk
density relationship more similar to the Tagish Lakethan to the Ivuna sample, which has a similar elemental composition to Ryugu. This result is in agreement with the elastic properties measured by Onodera
et al. [2] and suggests that in carbonaceous chondrites
with petrological classifications 1 or 2, thermo-mechanical properties may be dominated by mechanicaland structural features consisting of the matrix, inclusions, and voids inside the grain. The grain of the lowest thermal diffusivity in Ryugu samples do not havea smaller bulk density than that of other Ryugu
Figure 2 Thermal diffusivity vs. bulk density of Ryugu and carbonaceous
grains. Furthermore, the results of the thermal diffuchondrites.
sivity distribution analysis indicate that the decreasein thermal diffusivity is unlikely due to cracking because the angular distribution of the thermal diffusivity seemed almost isotropic. In other words, this suggests the possibility that there is a heterogeneous distribution of the pore structure or tiny inclusions
that reduce the thermal diffusivity while maintaining the bulk density.
To investigate the relationship between elastic wave velocity and thermal diffusivity, we additionally measured the primaryelastic wave (P-wave) velocities of some samples as follows: one grain of Ivuna (CI), one grain of Murchison (CM2), one grainof Tarda (C2-ungrouped), and three grains of Tagish Lake (C2-ungrouped). The pulse transmission method was used for themeasurements. Details of the measurements of the P-wave velocity are described in a previous report [7]. The result is shown in
Figure 3, and the reference value of Ryugu is from Ref. [3,5]. Figure 3 shows that there is a positive correlation between thermal diffusivity at the range of 0−2 km/s for the
P-wave velocities. However, for P-wave velocities above
2.0 km/s, the thermal diffusivity tends to approach a constant value for P-wave velocity. Although the number ofmeasurements is insufficient to clearly understand thecause of this trend, since the thermal diffusivity is more
susceptible for the structural factors than the elastic wave
velocity, it is possible that the structural factors in the grain
may differ around the P-wave velocity of 2.0 km/s (e.g.,whether the cracks are in a contact or non-contact at interface). The relationship between thermal diffusivity andelastic wave velocity will be able to provide an effective
basis for understanding the internal structure of Ryugu andchondrite grains, by increasing sampling numbers for the
Figure 3 Thermal diffusivity vs. P-wave velocity of Ryugu and carbocarbonaceous chondrites in petrological classifications 1 ornaceous chondrites.
2 and 3.
References[1] T. Yokoyama et al., Science, abn7850 (2022). [2] K. Onodera et al., ESS Open Archive, May 25 (2023). [3] T. Ishizaki etal., Int. J. Thermophys., 44(4), 51, 2023. [4] Soini et al., Meteorit. Planet. Sci. 55, 402–425 (2020). [5] Opeil et al., Icarus,
208(1), 449–454, (2020). [6] H. Y. McSween, Jr. and G. R. Huss, “Cosmochemistry,” Cambridge Univ. Press, 169 (2010). [7]Onodera et al., Proc. Jpn. Soc. Planet. Sci. Fall Mtg. 2023 (2023).

Spatial relationship between macromolecular organic matter and organic-bearing phyllosilicates in
Ryugu grain.
Toru Matsumoto1, Takaaki Noguchi2, Tohru Araki3, Takuji Ohigashi4, Yohei Igami2, and Akira Miyake2
1
The Hakubi center for Advanced Research, Kyoto University.2Division of Earth and Planetary Sciences, Kyoto University,
3
Institute for Molecular Science, 4High Energy Accelerator Research Organization.

Introduction: Regolith samples recovered from the C-type asteroid Ryugu show chemical and petrologicalcharacteristics similar to those of CI carbonaceous chondrites [e.g., 1-3]. They consist of primitive components of the earlysolar system, including water and organic matter, but are highly modified in the parent body by aqueous alteration. Insolubleorganic macromolecules (IOM) in Ryugu grains are the dominant components of organic matter in Ryugu’s materials [3]. The
chemical structures, distributions, and morphologies of the macromolecular organic matter can be tracers of the evolution oforganic materials in the interstellar medium, the protosolar disk, and the aqueous environment in the parent body of Ryugu [3].
Recent analysis of the interlayer spaces of phyllosilicate minerals in Ryugu grains suggested the presence of organic molecules
in clay structures [4, 5]. The infrared absorption band at around 3 µm obtained from Ryugu grains may come from N-Hbearing molecules trapped in the interlayers of phyllosilicates [6]. These results suggest that phyllosilicates have been affectedby organic matter during the aqueous alteration. Detailed investigation of the interlayer spaces of phyllosilicates and their
spatial association with macromolecular organic matter will provide insight into the interaction between minerals, water, andorganic matter in the parent body of Ryugu. In this study, we focused on carbon-rich regions in a Ryugu grain and examined
the spatial relationship between organic materials and phyllosilicates, together with their chemical features.
Methods: A Ryugu grain from the chamber A (grain No. A0142) was distributed by JAXA as a sample for theinternational announcement of opportunity and was used in this study. The surface features of the grain was observed using afield-emission (FE)-scanning electron microscope (SEM) (JSM-7001F). Electron-transparent sections were extracted from theregions of interest using a focused ion beam system (FIB Helios NanoLab G3 CX). Scanning transmission X-ray microscopy(STXM) imaging was performed to obtain X-ray absorption near edge structure (XANES) spectra from the sections. The
bonding structure of carbon was investigated using XANES spectra at the carbon K-edge (at 280 eV-320 eV). After STXM
analysis, the sections were observed using field-emission transmission electron microscope (TEM) (JEOL JEM2100F).
Results: Backscattered electron images of the grain surface show the concentration of organic matter embedded in thephyllosilicate matrix (Fig. 1a). Several carbon-rich spots were found on the grain surface. We investigated the largest carbonrich region with approximately 17×8×9 µm in size (Fig.1ab). Carbon-XANES spectra of the carbon-rich region include major
peaks of aromatic carbon (285 eV) and carboxyl carbon (288.5 eV), and those of phyllosilicate matrix in the vicinity of the
carbon-rich region show peaks of aromatic carbon (285 eV), carboxyl carbon (288.5 eV), aliphatic carbon (287.5 eV), andcarbonates (290.4 eV). TEM analysis showed that organic materials and fibrous phyllosilicates are finely intermixed in the
carbon-rich region. Hereafter, we call the carbon-rich region as the carbon-phyllosilicate aggregate (CPA). Distinct
morphologies of organic materials, such as the organic globules, were not identified in the CPA. The surrounding matrix
consists mainly of fibrous phyllosilicates, magnetite, iron sulfides, and carbonates. High-resolution TEM images showing
layered structures of the fibrous phyllosilicates (Fig. 1c) enabled us to investigate the interlayer distance of the phyllosilicates.
The majority of the fibrous phyllosilicates in the CPA and the matrix have interlayer distances of 0.7~0.75nm, and 1.0-1.2nm.
These values correspond to typical interlayer distances of serpentine and saponite in Ryugu samples, respectively [2]. On theother hand, fibrous phyllosilicates with interlayer distances of 1.23-1.35 nm were occasionally observed in the CPA and in thematrix close to the carbon-rich region (Fig.1c).
Discussion: The enrichment of aromatic and carboxylic carbon in the XANES spectra from the CPA is similar to thespectral features of highly-aromatic or aromatic macromolecular carbon in Ryugu samples [3]. The concentration of aromaticorganic matter may have occurred by redistribution and/or synthesis of organic matter during fluid activity in the parent body.
It is also possible that large chunks of organic matter have been incorporated during the initial accretion of the parent body, inthe form of primitive materials originated from the outer solar system [7]. The appearance of aliphatic carbon in the matrix is
consistent with the previous XANES study of Ryugu samples, in which aliphatic organics were detected in association withphyllosilicates [8]. Previous X-ray diffraction measurements of Ryugu samples detected 001 reflection of smectite at 1.26 nm[4]. The relatively large interlayer distance was interpreted as the expansion of the interlayer space due to the presence oforganic molecules [4]. Accordingly, the interlayer distances of 1.25-1.35 nm found in our sample suggest that organic species

are intercalated into the phyllosilicates. The spatial relationship between the CPA and the possibly organic-bearing
phyllosilicates suggests that macromolecular organic matter could have interacted with surrounding phyllosilicates during
aqueous alteration, as suggested by analyses of carbonaceous chondrites [9, 10].

Figure 1. SEM and TEM analysis of the carbon-rich region of Ryugu grain (A0142). Backscattered electron image (a) and bright-field TEM
image (b) of the carbon-phyllosilicate aggregate (CPA). Arrows indicate the interface between the CPA and surrounding phyllosilicate
matrix. (c) High-resolution TEM image of fibrous phyllosilicates near the CPA. Interlayer distances are shown in the figure.

References: [1] Yokoyama et al. 2022. Science 379.6634, eabn7850. [2] Nakamura et al. 2022. Science 379.6634, eabn8671.
[3] Yabuta et al. 2023. Science 379. 6634, eabn9057. [4] Viennet et al. 2023. Geochem. Persp. Let. 25, 8-12. [5] Damien et al.
2023. Meteoritics & Planetary Science under review. [6] Pilorget et al. 2022. Nat. Astron. 6, 221-225. [7] Duprat et al. 2010.
Science 328, 742-745. [8] Ito et al. 2020. Nature Astron. 6:1163-1171. [9] Garvie and Buseck, 2007. Meteoritics & Planetary
Science 42, 2111-2117. [10] Guillou et al. 2014. Geochim. Cosmochim. Acta, 131, 368-392.

Analysis of a thermal correction method for the MIRS infrared spectrometer:preparation for the future observations of the Martian moons Phobos and Deimos
G. David1, M. Delbo2, A. M. Barucci1, F. Merlin1, P. Beck3, S. Fornasier1 and G. Poggiali1
1
LESIA, Observatoire de Paris, Université Paris Cité, Université PSL, Sorbonne Université, CNRS, Meudon, France
2
Laboratoire Lagrange, Observatoire de la Côte d’Azur, Université Côte d’Azur, CNRS, Nice, France
3
Institut de Planétologie et d’Astrophysique de Grenoble, OSUG/CNRS, 122 rue de la piscine, F-38000 Grenoble, France
Introduction: The Martian Moon eXploration (MMX) mission is scheduled to be launched to the Martian system in
2024 [1]. The scientific payload will include the MMX InfraRed Spectrometer (MIRS, [2]), an instrument dedicated to the studyof Mars and its satellites: Phobos and Deimos. MIRS data will contribute, together with the other instruments and the sample
return analysis, to understand the origin of the two Martian moons. It will help to decipher whether they are captured asteroids
or rather formed by accretion from a debris disk, the latter resulting from a giant impact between Mars and a planetesimal. In the
spectral range covered by MIRS (0.9-3.6 µm), several components of geological interest will be studied through their spectral
properties such as anhydrous and hydrous silicate minerals, water ice, or organic matter. Constraining the presence and relative
abundance of these phases will help to determine the Martian moons' formation processes. However, several absorption bands
associated with these compounds are in the spectral region beyond ~2.5 µm, where the signal collected by the instrument is acombination of reflected sunlight and thermal emission from the observed surfaces. The thermal emission - the so-called thermal
tail - can strongly modify the continuum of the spectra and the width of the absorption bands. Consequently, before proceeding
to the mineralogical analysis and interpretation of future MIRS data, a thermal emission correction is needed. In this study, asimple method of thermal emission correction is tested on synthetic data to evaluate its potential and limitations.
Method: The thermal tails of spectra are mainly controlled by the surface's temperatures, roughness and emissivity.
For airless bodies, such as Phobos and Deimos, the surface conditions can be highly fluctuating, between ~130 K and ~300 K[3]. Temperature and emissivity are often not well-constrained on planetary surfaces, but they can be estimated directly from theinfrared spectra. In this work, we deliberately explored a simple empirical method of thermal tail removal, based on Planck
blackbody fit, owing to the MIRS instrument will provide a large amount of data and a method running quickly will savecomputing time and make it easier data interpretation during MMX flight operations. We used the approach from [4], which was
originally developed to correct the Moon Mineralogy Mapper (M3) observations onboard the Chandrayaan-1 spacecraft. Thisapproach is iterative and uses the assumption that the continuum of the reflected solar component is approximately linear beyond
2.5 µm. The signal at short wavelengths (with no thermal contribution) is used to extrapolate the reflected component in thethermal tail part of the spectra at a given wavelength. The differences between the projected reflectance and the original spectra,
corresponding to the thermal contribution, are then fitted with a blackbody Planck function radiation, and a temperature can bederived. Emissivity (e) is determined by using the projected I/F (the signal collected by the instrument normalized to the solarflux) at a specific wavelength and Kirchhoff’s law (e=1-I/F). Here, we perform two iterations to adjust the temperature, using inthe second run the previous corrected spectra. While in the first iteration, emissivity is considered as constant with wavelength,
the second iteration will consider a wavelength‐dependent emissivity (i.e., the Kirchhoff's law is used for each wavelength).
Synthetic data: Different spectral datasets were generated for the purpose of this study by means of a thermophysicalmodel [5], which calculates thermal infrared spectra of airless bodies or sub-portions thereof as a function of several physicalparameters such as albedo, roughness, thermal inertia, rotation period, direction of the rotation axis, as well as illumination andviewing geometry. The first dataset corresponds to seven synthetic reflectance spectra thought to be reasonably analogous to
Phobos, for which thermal contribution at different temperatures from 262 K to 329 K has been added. In this first set ofsimulations, the scene corresponds to a flat facet of the Phobos shape model in nadir view. The second dataset includes the same
parameters but this time, roughness has been generated by adding hemispherical section craters into the facet. This makes suchthat sub-facets with different inclinations with respect to the sun and the instrument compose the field of view. Each sub-facet
contributes to the thermal infrared flux with its own temperature, which depends on the geometry relative to the sun. Finally, thelast dataset is similar to the previous one but includes a fictitious absorption band centered at 3.2 µm, to study its effect onthermal correction. In all our simulations, e has been set to 0.9, which is thought to be consistent with the Martian moon surfaces.
Results: The first dataset is used to test the consistency between the temperature retrieved by the thermal correction
model and the temperature used as input by the thermophysical model. Our results show that the first iteration gives an averageof ∼0.8 K of difference from the true temperature, while the second iteration increases the error on temperature retrieval with anaverage of ∼1.4 K of difference. These results are consistent with the experiment made by [4], who found that the derived
temperature by this approach of heated basalt in the laboratory was around 1 degree of the true measured temperature. The
emissivity predicted by the model is also very consistent with the one used in the thermophysical model (e=0.9) to generate thedata. The first iteration predicts e~0.88 for all temperatures, whereas the second iteration predicts emissivity within 0.86-0.88.
To determine the efficiency of the thermal correction, we calculated the mean absolute percentage error (MAPE), whichquantifies the difference between each corrected spectrum and its spectrum of reference (i.e. spectrum generated without thermal
( )*

+,,

contribution) that can be expressed as MAPE = ∑!l"#.% µ' $ l( l $ ! , where yl and xl are the I/F values of the reference andlcorrected spectra for each wavelength in the thermal part (i.e., l>2.5 µm). For the first data set, we found that corrected spectra
have respectively MAPE scores of ∼1.25% (σ=0.5 %) and ∼0.21% (σ=0.2%) on average for the first and second iterations,which is pretty good. For the second dataset, including roughness in the simulated scene, the complexity of the data slightly
degrades the thermal correction (Figure 1, left panel). For all spectra, a small rise in reflectance can be observed after the thermal
correction at the edge of the spectra due to an under-correction. Nevertheless, this residual thermal contribution is quite negligible
as expressed by the good MAPE scores. On average, they are respectively equivalent to ~3.1% (σ=1.1%) and ~1% (σ=0.49%),
for the first and second iterations, which is satisfying. Emissivity predicted by the model (eiteration 1~0.88, eiteration 2= 0.86-0.88) is
still very consistent with the reference and is similar to the emissivity guessed for the first dataset.

Wavelength (!m)

Wavelength (!m)

Wavelength (!m)

Wavelength (!m)

I/F

I/F

Wavelength (!m)

Wavelength (!m)

Wavelength (!m)

I/F

I/F

T=262 K

Wavelength (!m)

I/F

T=262 K
I/F

Wavelength (!m)

T=302 K
I/F

I/F

T=302 K

Wavelength (!m)

I/F

I/F

T=329 K
I/F

I/F

T=329 K

Wavelength (!m)

Wavelength (!m)

Figure 1. Results of thermal correction of several synthetic reflectance spectra of Phobos generated by means of a thermophysical model [5].
Spectra with thermal emission (red lines) are compared to the two iterations of thermal removal (first and second iterations are represented
respectively in blue and orange). Green spectra correspond to the synthetic spectra simulated without the thermal contribution and they serve
as a benchmark. Dash lines correspond to the Planck functions of the first and second iterations (respectively in blue and orange). The left
panel shows the results for the second set of synthetic data, whereas the right panel corresponds to the third dataset with absorption bands.

For the synthetic spectra containing a synthetic absorption band at 3.2 µm, the model of thermal correction seems to be still
efficient (Figure 1, right panel). The MAPE scores of these spectra remain quite good with an average of ~1.6% (σ=0.61%) and~0.8% (σ=0.01 %). Emissivity is still overall in line with the one used to generate the data (eiteration 1~0.92, eiteration 2=0.89-0.92).
Despite the relatively good MAPE scores, a drop in reflectance can be observed at the edge of the spectra (beyond 3.45 µm),
which was also observed in the work made by [4]. In terms of band depths, the differences with the references are in averages
respectively equivalent to ~7.3% (σ=0.96%) and ~4.7% (σ=4.2%) for spectra corrected with one and two iterations.
Conclusion: In this study, we tested on simulated data of Phobos, the thermal correction method developed by [4]. Our results
show that this method appears to be usable for the thermal correction of future MIRS observations. The correction seems to beefficient, especially for high surface temperatures. Moreover, by improving each time the MAPE scores with the second run ofthe data treatment, we confirmed the efficiency of the iterative approach. We also quantified the impact of the thermal correction
on the absorption bands and found an overestimate of the band depths limited to a few percent. This is an ongoing work to
improve the thermal tail removal in preparation for the planned activity of MIRS during the orbital phase of MMX mission.
References: [1] Kuramoto, K., et al., (2021), Earth Planets Space. 74(1), 1-31. [2] Barucci, M. A., et al., (2021), Earth, Planets,
and Space. 73-211. [3] Giuranna, M., et al. (2011), Planetary and Space Science. 59(13), 1308-1325. [4] Clark, R. N., et al.,(2011), Journal of Geophysical Research: Planets, 116(E6). [5] Delbo, M., et al., (2015), Asteroids IV, 1, 107-128.

A Comparative Carbon-XANES and -EELS study of Organic Material from Asteroid 162173
Ryugu and Ivuna.
H. G. Changela1,2, L. Petera1,3, J. C. Bridges4, Y. Kebukawa5, L. Hicks6, N. Topping4, C. S. Allen7, E. Chatzitheodoridis8, M
Ferus1
1 Department of Spectroscopy, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Czechia. 2
Department of Earth & Planetary Science, University of New Mexico, New Mexico, USA. 3 Department of Inorganic
Chemistry, Charles University in Prague, Czechia. 4 Space Research Centre, School of Physics and Astronomy, University ofLeicester, UK. 5 Department of Earth & Planetary Sciences, Tokyo Institute of Technology, Japan. 6 School of Geology,
Geography, and the Environment, University of Leicester, UK. 7 electron Physical Science Imagine Centre, Diamond Light
Source, Oxford, UK. 8 School of Mining, National Technical University of Athens, Greece. Email: changela@unm.edu
Introduction The arrival of samples from carbonaceous asteroids 16273Ryugu [1] 101955Bennu [2] provide a window into
early Solar System organic evolution on a known asteroid. Organic material (OM) from carbonaceous asteroids is currently
most accurately characterised in situ by coordinating synchrotron based scanning transmission X-ray microscopy (STXM) withtransmission electron microscopy (TEM) on samples. Organic functional chemical variations can be measured by Carbon Kedge X-ray absorption near edge structure (XANES), whilst organic morphology and its mineral setting is characterised bysubsequent TEM. Carbon-energy electron loss spectroscopy (EELS) offers the same possibility as C-XANES but with theadvantage of being performed in a stand-alone TEM. Here we compare C-EELS with -XANES on OM from Asteroid Ryugu
and the Ivuna CI chondrite prepared by dual beam focused ion beam (FIB)- scanning electron microscopy (SEM) and ultra
microtome to assess the effects of electron beam dosage by all techniques.
Methods Two adjacent ~100 nm thick lamella were prepared using FIB-SEM (Fig. 1). Lamella 1 was prepared using Xeplasma FIB-SEM with the Helios 5 Hydra DualBeam (CEITEC, Masaryk University (MUNI), Czechia) and analysed by TEMC-EELS with the JEOL ARM200CF (ePSIC, Diamond Light Source, UK), followed by STXM-XANES at Beamline BL19A
of the KEK Photon Factory, Japan. Lamella 2 (Fig. 1) was prepared by Xe-plasma FIB-SEM with the TESCAN AMBER X(TESCAN ORSAY holding a.s., Brno, Czechia) followed by STXM-XANES (i.e. no TEM) at the photon factory. Microtome
samples of Ivuna were prepared using methods in [3] at CEITEC-MUNI with a Leica UC7. Organic material in a lamella from
Ryugu grain C0105-03500000 provided by the Hayabusa-2 preliminary examination SAND team prepared using the
University of Leicester’s FEI Quanta 3D was also measured by C-EELS at ePSIC.
C-EELS FIRST SEM-TDL (5 KV)

Ivuna Grain SEM-ETD (5 KV)

C-XANES FIRST SEM-ETD (2 KV)

5 μm

1 μm

50 μm

Figure 1. SE image of a grain of Ivuna on carbonate sticky and coated with 5 nm Au. Large cross section at the front of the grain was thelocation where 2 adjacent FIB lamella were extracted: one with C-K edge EELS then XANES (left extraction) and the other direct XANES(right lamella). Blue and red rectangle mark the ROIs where the EELS and XANES maps were taken (Fig. 2).

Results Eelectron beam exposure to chondritic OM during SEM, TEM and EELS changes its functional chemistry, in both its
macromolecular and particularly in soluble/insoluble form within phyllosilicate (Fig. 2). A peak at ~290.4 eV attributed tocarbonate -O-C=O-O- bonds is observed under 200 KV electron doses by TEM, STEM imaging and by EELS spectral
mapping. This feature is absent from microtome samples measured by XANES. A bulge in the EELS spectra consistent withamorphous an carbon σ * peak (~288 – 315 eV) is found in organic particles. The carboxylic (288.5 eV) peak found in diffuse
OM within phyllosilicates (e.g. Graph 2) is replaced by the carbonate one at 290.4 eV (Graphs 1 & 4).

Figure 2. Carbon-EELS and -XANES on the Ivuna lamella and Ryugu sample.

Discussion The amount of radiation damage has been shown much lower in STXM-based XANES spectroscopy than in TEMbased EELS [8]. Our observations particularly of organo-carbonate bonding in diffuse OM shows its formation sensitive to ebeam exposure rather than X-ray exposure. This was also identified by [9] in terrestrial coals imaged with 5KV SEM during
FIB lamella preparation. Furthermore, Yabuta et al. 2023 [5] reported the lack of any carbonate peak in microtome samples
measured by XANES, but occurring in FIB sections with organic particles and diffuse OM in Ryugu samples (referred to as
clay bound OM in their study). Our microtome samples of CI chips also lack this peak in any XANES measurements,suggesting that e-beam exposure during FIB-SEM preparation also formed the organo-carbonate bonds observed in previous
STXM studies [e.g. 10] and recently in [5]. However, potential mixture of indigenous organo-carbonate cannot be ruled out.
Conclusions Chondritic OM is sensitive to electron radiolysis particularly by the formation of organo-carbonate bonding,
although the formation mechanism is unclear. Carbon-EELS of organic particles also convolute the 288.5 eV carboxyl peakby an amorphous bulge. This means that synchrotron XANES coordinated with subsequent TEM more accurately provides ameasure of functional chemical variation of chondritic OM than EELS-TEM.
FIB-SEM lamella preparation of chondritic matrices require electron energies lower than 5KV (e.g. 1.5KV) during imaging
to minimize e-beam damage by radiolysis. It is unclear though whether SEM lower than 5KV could prevent the formation ofthis carbonate -O-C=O-O- ~290.4 eV feature, and how other regions of C-XANES and -EELS spectra are effected.
References [1] Yada T. et al. 2014. Nature Astronomy 6:214-220. [2] Lauretta et al. 2015. Meteoritics & Planetary Science
50:834-849. [3] Noguchi et al. 2020. Life 10(8):135. [4] Yuan J. & Brown L. M. 2000. Micron 31: 515-525 [5] Yabuta H. et al.
2023 Science 679:6634. [6] Garvie and Buseck 2007. Meteoritics & Planetary Science 42(12):2111-2117. [7] Changela. H. G.
et al. 2023. Abstract #2848. 54th LPSC. [8] Wang J. et al. 2009. Journal of Electron Spectroscopy and Related Phenomena
170:25-36. [9] Bassim N. et al. 2012. Journal of Microscopy 245:288-301. [10] Changela. H. G. et al. (2018) Meteoritics &Planetary Science 53:1006-1029.
Acknowledgements Special thanks to the Hayabusa-2 preliminary examination SAND team for useful discussions and access to Ryugu
sample C0105-03500000 in this study. We thank Diamond Light Source and electron Physical Imaging Centre ePSIC (instrument EO1,
proposal MG30752). We also thank TESCAN GROUP, a.s. for use of their instrumentation and Dr. Hana Tesarova for her help. We
acknowledge CF CryoEM of CIISB, Instruct-CZ Centre, supported by MEYS CR (LM2023042) and European Regional Development FundProject UP CIISB" (No. CZ.02.1.01/0.0/0.0/18_046/0015974).We thank KEK Photon factory for use of Beamline BL 19A for STXM.

Non Destructive Analyses of (Extra-) Terrestrial Materials by Combining Digital Optical
Microscopy with LIBS (Element Analyses) and Micro Raman Spectroscopy – A New Approach
V.H. Hoffmann1,2, M. Junge1,2, F.Hentschel2, W.W. Schmahl1,2, M. Kaliwoda1,2
Department of Earth- and Environmental Sciences, University of Munich; 2Mineralogical State Collection Munich (MSMSNSB), Munich, Germany.

1

In this contribution we will present a new approach for the full analyses of highly sensitive or rare, valuable (extra-) terrestrial
materials. The method is nearly non-destructive and will significantly reduce the material loss or unwanted influence to thesamples / particles under investigation. The approach was specifically developed for returned samples for example fromasteroids (Hayabusa 1,2; Osiris Rex, and others) [1,3,4]. It allows to obtain high resolution (in x/y/z) and sensitivity
mineralogical data with minimum sample modifications. All investigations can be preformed in atmospheric conditions
without any preparation, so directly on the samples as obtained from the various sources.
Due to the significant brecciation and very fine grained matrix / phases, experiments on primitive carbonaceous chondrites arequite complex. Many phases in these primitive space materials are extremely sensitive against (even minor, or local) heating
effects, and therefore any kind of preparation (cutting/grinding etc.), specifically in terrestrial atmospheric conditions should be
minimized. In order to avoid any such effects we prefer to investigate - whenever possible - naturally broken unpreparedsample materials. The representativity of the data obtained on the often small amounts of available sample material was also
topic of our studies: large sets of high resolution mappings in 2D/3D can help to overcome the problem of tiny samples /fragments. Our experiences from the earlier investigations on Hayabusa 1 materials (asteroid Itokawa) were highly profitablein this context [2].
(1) Digital Optical Microscopy
Up to now, the surface morphology and mineralogy of the samples is/was pre-investigated routinely by SEM whereby in mostcases carbon (or other) coatings are basic requirement. Raman experiments on such samples were then impossible because
coatings on rough/raw samples cannot be removed and even more serious, investigating carbon phases was also blocked. High
resolution digital microscopy (Keyence VHX950F system) can completely overcome all these severe disadvantages. The
technique provides full control of sample materials by pre-selection of particles/areas in 2D/3D for the Raman experiments
planed exactly on the same samples as a follow-up step (3). The capabilities of our approach will be demonstrated on aselected set of meteorite samples and terrestrial equivalents. The methodology is very well suited for a fast characterization andclassification of tiny samples / fragile materials such as carbonaceous chondrites or returned samples [1-5].
(2) Element Analyses by LIBS
As a next step element analyses can directly be performed with the same instrument on the pre-selected spots or particles by
LIBS – LASER Induced Breakdown Spectroscopy. No vacuum, coating or pre-preparation are required which for example
means no limitations to sample sizes or shapes. The short-time LASER – material interaction causes only very minor material
consumption (LASER spot diameter about 10 microns). Within few seconds the element spectra can be obtained for a large
number of elements.
(3) Micro Raman Spectroscopy
Finally the samples or particles under investigation can be transferred to our Micro Raman Spectrometer. As a last step of ourapproach, a large number of Raman spectra can be obtained by high resolution mapping of the pre-selected spots or particles.
We use a Horiba Jobin Yvon Micro Raman Spectrometer (XploRa One) at the Mineralogical State Collection Munich (MSM)
for our experiments which is best suited for investigating non-prepared surfaces - to avoid any influence on preparationsensitive extraterrestrial phases or tiny rare materials. Raman spectroscopy is a mostly non-destructive technique for systematic
phase analyses specifically on very small, < 50-100 µm sized particles or even subsurface inclusions. Performing successful
Micro Raman experiments on highly fragile space materials such as carbonaceous chondrites, requires the design of a highlysophisticated experimental setup to avoid or at least minimize alteration effects already during the measurements on the one
hand and to guarantee a reasonable signal/noise relation on the other.
Further details and a set of examples will be provided by our iposter contribution.
Acknowledgements
We highly appreciate the support of Th. Koch from Keyence Germany GmbH, specifically concerning the application anddetailed test of LIBS on a set of our samples.
References[1] https://www.isas.jaxa.jp/en/missions/spacecraft/past/ hayabusa.html[2] Mikouchi T. and Hayabusa Consortium, 2014. Earth, Planets and Space, 66/82, 9pp[3] https://mars.nasa.gov/mars2020/[4] https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars[5] Meteoritical Bulletin Database, 09/2023.

Study on Similar Continued Organic Life Systems on the Rocks of Water Planet Earth
Yasunori MIURA
Department of Earth System Sciences, Faculty of Science, Yamaguchi University

Introduction: Solid rock (mixed to pure Si, Ca, or Fe groups) system of active Earth as A3MS are different with rocky solid(mixed Si, Ca, or Fe groups) system od inactive Asteroids and the Moon as 1MS, shown other paper in this volume [1]. However,organic compounds to life system of Carbon (C) groups are light elements (C, H, O, N) with rapid reaction on higher pressure
and temperature (higher PT) condition different from rocky “mineral” as slower reaction in lower pressure and temperature (lowPT) condition, especially its carbon behaviors as unclear sources and existence between rocks and air-fluid mixtures. Therefore,
there are many unsolved problems of 1) condition (higher to lower PT) to form organic compounds (single to higher molecules),2) carbon-bearing rocks on natural rocks formation of active Earth plane and inactive Asteroids, and 3) Artificial sources ofcarbon-bearing grains to be mixed with inactive Asteroids and active Earth rocks. The main purpose of the paper is to make sureorigin and sources organic carbon formation on active Earth form called as Active Three Material States (A3MS) where almost
products might be mixed with carbon during heating on global and local sites of active and inactive planet. [1-3] (Table 1).
Formation of organic molecules from two molecules during higher PT on inactive Asteroids: Mixed rocks with lightelements including carbon rapidly cooled from air and fluid after various impacts are lightly connected with rocky grains of Sisystem, where it is difficult to observed carbon-fixed to rocky Si system grains (except analytical -electron micrography) [5].
Although the carbon-bearing grains and molecules are formed easily on active water planet Earth as A3MS system, it’s difficult
to be formed and maintained for these grains and molecules for organic compounds because there is no closed system on airless
Asteroids and the Moon even in higher PT events (by collisions etc.) by evaporated or quenched inorganic grains. This is the
major difference with active water-planet Earth for its formation and remained sure to closed system as a A3MS system. Thissuggests that there are no static molecules of pure water or carbon dioxide (to make static organic molecules) at lower temperatureon airless Asteroids and the Moon (except increases processes to make original two molecules continuously on inactive body).
However, carbon-bearing rocky grains are formed as quenched inorganic grains and might be formed fluid or vapor stated atincreased higher PT condition even in inactive celestial bodies of an Asteroids. [4,6]Possible man-made sources of terrestrial carbons on in active celestial bodies: If we might use any metallic products
formed by normal industrial sites with higher temperature (as ca. 0.2 to 6.5wt.% CO2 contents in steel materials generally), it
might be leaked in inactive celestial bodies of an Asteroids and the Moon (as in impacted sample collections or cratering).
Possible cases of the formation of organic compounds from fluids and carbon dioxides on inactive celestial bodies: On
inactive Asteroids and the Moon, light element CHO-system groups are easily formed from products contained carbon elements(cf. steel parts) with impacted sample collections and/or analytical procedures by collision less-shock wave reactions by electron,
ion and laser beam bombardments in analytical cambers and inactive celestial bodies (by natural beams from Universe and theSun) are expected carefully to be interpreted on the paper [6]. In short, various mixed aggregates can be observed in many partsof the Asteroids with carbon-bearing grains before forming the Moon or Mars planet as intermediate solid-aggregated rocks
before forming the water planet Earth with other active life-A3MS system groups as a carbon-shifted system.

Table.1 Comparison of probable organic materials of Earth, Asteroids and other extraterrestrial bodies.
Celestial bodies

Carbon-bearing organic compounds

Organic Life System

Earth (water planet)

Active three material states (A3MS) system

Yes. Non-mineral elements system separated

Asteroids, the Moon (Mars)

Inactive material state (1MS), Sputtering?

Exist as carbon-bearing grains (mixture)Summary: The present work has been summarized as follows.
(1) Active planet model A3MS can be formed organic compounds and pure air gas and liquids.
(2) Possible man-made sources of terrestrial carbons on in active celestial bodies.
(3) Possible cases of the formation of organic compounds from fluids and carbon dioxides on inactive bodies are existed.

References: [1] Miura Y. (2018) IMA-22,1189. [2] Miura Y. (2023) JAMS. E5-15. [3] Miura Y. (1996) Shock-Wave Handbook(SV, Tokyo),1073-1209. [4] Miura Y. and Kato T. (1993) AIP, 283, 488-492. [5] Miura Y. (1992) Celestial Mechanic. &Dynamical Astro. (KA), 54, 249-253. [6] Y. Miura (2023) In this volume.