Hayabusa 2021 Symposium Schedule (Online Meeting)version. 20211111(8th ISAS Symposium of the Solar System Materials )16th(Tue)‐17th(Wed) of November 2021
Oral : Zoom Meeting (10+5 min for Invited and normal talks, 7+3 min for 10 min short talks)
Poster : Zoom Meeting Breakout Rooms
Non‐real time discussion : Slack
Day‐1 (Nov 16th) : Oral Session
JST

GMT

EST

PST

No.

(‐1day) (‐1day)

Title
Session‐0 : Opening session:

Author/Presenter

InvitedT. Okada

09:45

00:45

19:45

16:45

S0‐1

Opening and Logistics

Tatsuaki Okada

09:50

00:50

19:50

16:50

S0‐2

Status of JAXA Curation activity and future plan

Tomohiro Usui

Session‐1: Ryugu sample : S. Tachibana, T. Usui
10:00

01:00

20:00

17:00

S1‐1

An overview of initial descriptions for samples returned from C‐type asteroid Ryugu

Toru Yada

Invited

10:15

01:15

20:15

17:15

S1‐2

First NIR hyperspectral imaging of Hayabusa2 returned samples by the MicrOmega microscope within the ISAS Curation Facility

Cedric Pilorget

Invited

10:30

01:30

20:30

17:30

S1‐3

Initial analysis of Hayabusa2 returned samples from asteroid (162173) Ryugu

Shogo Tachibana

10:45

01:45

20:45

17:45

S1‐4

Progress of chemical characterization of asteroid Ryugu samples

Hisayoshi Yurimoto

Invited

11:00

02:00

21:00

18:00

S1‐5

Initial analysis of “stone” size Ryugu samples: current status

Tomoki Nakamura

Invited

11:15

02:15

21:15

18:15

S1‐6

Mineralogy and surface modification of small grains recovered from the asteroid 162173 Ryugu

Takaaki Noguchi

Invited

11:30

02:30

21:30

18:30

S1‐7

Initial Analysis of Volatile Components in the Hayabusa2 Samples

Ryuji Okazaki

Invited

11:45

02:45

21:45

18:45

S1‐8

An initial look at the distributions and compositions of organic macromolecules in the asteroid Ryugu samples

Hikaru Yabuta

Invited

12:00

03:00

22:00

19:00

S1‐9

Soluble Organic Matter (SOM) analysis of the Hayabusa2 samples: The first results

Hiroshi Naraoka

Invited

12:15

03:15

22:15

19:15

<Lunch break>

All

13:30

04:30

23:30

20:30

S2‐1

A first look at the interior and exterior of Ryugu preserved in samples collected by Hayabusa2

Eizo Nakamura

Invited

13:45

04:45

23:45

20:45

S2‐2

The C‐type asteroid Ryugu: A first detailed look by Phase2 Curation Kochi (Ph2K)

Motoo Ito

Invited

14:00

05:00

00:00

21:00

S2‐3

JAXA Detailed Description ‐Variation of surface characteristics of Ryugu returned samples‐

Aiko Nakato[Group Photo‐1]

Sessions‐2 : Ryugu Sample (Cont.) : R. Brunetto, A. Nakato

14:15

05:15

00:15

21:15

S2‐4

Overview of the features of returned samples from the C‐type asteroid 162173 Ryugu based on optical microscope observations and their weights

Akiko Miyazaki

10 min

14:25

05:25

00:25

21:25

S2‐5

Initial description of Ryugu returned samples: characteristics of individual grains by FT‐IR analysis

Kentaro Hatakeda

10 min

14:35

05:35

00:35

21:35

S2‐6

MicrOmega detections of C‐rich phases in Ryugu returned samples within the Hayabusa2 JAXA Extraterrestrial Curation Center

Jean‐Pierre Bibring

14:50

05:50

00:50

21:50

S2‐7

MicrOmega detections of carbonates in Ryugu returned samples within the Hayabusa 2 JAXA Extraterrestrial Curation Center

Damien Loizeau

10 min

15:00

06:00

01:00

22:00

S2‐8

The 2.7μm OH band in different grains of Ryugu from the two collection sites, as seen by MicrOmega in the Hayabusa2 Curation Facility

Tania Le Pivert‐Jolivet

10 min

15:10

06:10

01:10

22:10

S2‐9

Microscale diversity of H, C, and N isotopes in asteroid Ryugu

Larry R. Nittler

15:25

06:25

01:25

22:25

S2‐10

Diversity of Insoluble Organic Matter at the Nanoscale in Asteroid Ryugu

Rhonda Stroud

15:40

06:40

01:40

22:40

S2‐11

Infrared transmission spectra of Ryugu particles and their unique adsorption behavior

Yoko Kebukawa

15:55

06:55

01:55

22:55

S2‐12

Thermal history of Ryugu based on Raman characterization of Hayabusa2 samples

Lydie Bonal

16:10

07:10

02:10

23:10

S2‐13

Elemental and isotopic compositions of organic grains from asteroid Ryugu

Laurent Remusat

16:25

07:25

02:25

23:25

16:40

07:40

02:40

23:40

S3‐1

Exposure Conditions of Samples Collected on Ryugu’s Two Touchdown Sites Determined by Cosmogenic Nuclides

Kunihiko Nishiizumi

16:55

07:55

02:55

23:55

S3‐2

Small grains from Ryugu: handling and analysis pipeline for Infrared Synchrotron Microspectroscopy

Stefano Rubino

17:10

08:10

03:10

00:10

S3‐3

Preliminary results from FTIR hyper‐spectral imaging campaign on Ryugu small grains and fragments.

Zelia Dionnet

17:25

08:25

03:25

00:25

S3‐4

Iron valence state and mineralogy in particles from asteroid Ryugu

Mathieu Roskosz

17:40

08:40

03:40

00:40

S3‐5

Three‐dimensional analysis of Ryugu sample particles using X‐ray nanotomography.

Akira Tsuchiyama

17:55

08:55

03:55

00:55

S3‐6

Surface morphologies and space weathering features of Ryugu samples

Toru Matsumoto

18:10

09:10

04:10

01:10

S3‐7

CNHOS contents with their isotopic compositions and preliminary organic profiles from the Hayabusa2 samples

Yoshinori Takano

18:25

09:25

04:25

01:25

S3‐8

Compound distribution determined by nanoLC‐Orbitrap MS

François‐Régis Orthous‐Daunay

18:40

09:40

04:40

01:40

S3‐9

Highest molecular diversity and structural complexity revealed with ultrahigh resolution mass spectrometry and nuclear magnetic resonance spectroscopy of Ryugu
Philippe Schmitt‐Kopplin´s samples

18:55

09:55

04:55

01:55

<Coffee Break>Sessions‐3 : Ryugu Sample (Cont.) : H. Sugahara, D. Yamamoto

Discussion on Ryugu sample

S. Tachibana (Lead)[Group Photo‐2]AllAn overview of initial descriptions for samples returned from C-type asteroid Ryugu.
T. Yada1, M. Abe1, A. Nakato1, K. Yogata1, A. Miyazaki1, K. Kumagai2, K. Hatakeda2, T. Okada1, M. Nishimura1,
S. Furuya1,3, M. Yoshitake1,4, A. Iwamae2,5, Y. Hitomi2, H. Soejima2, K. Nagashima1, R. Sawada2, L. Riu1,6, L. Lourit6,
C. Pilorget6, V. Hamm6, D. Loizeau6, R. Brunetto6, J.-P. Bibring6, Y. Cho3, K. Yumoto3, Y. Yabe3, S. Mori3, S. Sugita3,
S. Tachibana1,3, H. Sawada1, K. Sakamoto1, T. Hayashi1, D. Yamamoto1, R. Fukai1, H. Sugahara1, H. Yurimoto7, T. Usui1,
S. Watanabe8, Y. Tsuda1
1Inst. Space Astronaut. Sci., Japan Aerosp. Explor. Agency (JAXA), Kanagawa 252-5210, Japan(yada@planeta.sci.isas.jaxa.jp), 2Marine Works Japan Ltd., Yokosuka 237-0063, Japan, 3UTOPS, Grad. Sch. Sci., Univ.
Tokyo, Tokyo 113-0033, Japan, 4Japan Patent Office, Chiyoda-ku, Tokyo 100-8915, Japan, 5Toyo Univ., Bunkyo-ku, Tokyo
112-8606, Japan, 6Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91400 Orsay, France, 7Dept. Earth Planet.
Sci., Grad. Sch. Sci., Hokkaido Univ., Hokkaido 060-0808, Japan, 8Dept Earth Planet. Sci., Grad. Sch. Sci., Nagoya Univ.,
Nagoya 464-8601, Japan.
Introduction: Hayaubsa2 spacecraft operated by JAXA explored a near-Earth asteroid 162173 Ryugu from Jun 2017 to Nov
2019 [1]. During the exploration, the spacecraft accomplished touchdown sampling on the asteroid’s surface in Feb and Jul of2019 [2]. The samples recovered by the first touchdown were stored in the Chamber A of a sample catcher and those by thesecond one were in the Chamber C [2]. The sample catcher was sealed in a sample container, which was set in a reentry capsuleof the spacecraft, and the capsule was returned to the Earth, the Woomera Prohibited Area in South Australia, on 6 Dec 2020 [2,3].
Extraction Procedures for Ryugu samples: As the container was transported from Australia to Japan by air and arrived atcleanrooms of the Extraterrestrial Sample Curation Center (ESCuC), it was disassembled to remove unnecessary parts andcleaned on its surface in the cleanrooms and introduced into the clean chamber (CC) 3-1 to be evacuated to high vacuum [2, 3].
In the static vacuum condition, the container was opened and the sample catcher was extracted from the container. The catcher
was transported to the next chamber, CC3-2, and a lid of the Chamber A of the catcher was removed from the catcher and a few
mm-size particles were recovered from the Chamber A to a quartz glass container in vacuo. Then the catcher with rest of samples
was transported to the next chamber, CC3-3, then the catcher handling environment have changed from vacuum to purified
nitrogen condition. Hereafter, all the extraction works and initial descriptions have been done in this purified nitrogen conditionin the clean chambers. The catcher was firstly measured with a balance equipped in the chamber CC4-2 to confirm the bulk
samples’ weight in it, to be 5.4 grams [3]. Then it was dismantled with catcher handling tools in the chamber CC4-1 to recoversamples from each chamber of the catcher to sapphire dishes of 23mm in diameter.
Initial descriptions for bulk and individual Ryugu samples: Each of the bulk samples in the dishes were observed andphotographed with a stereomicroscope equipped above the chamber CC4-2. Then they were also measured with the balance for
their bulk weights to be 3.2 grams and 2.0 grams from the from the Chamber A and C, respectively [4]. They were then analyzed
with a Fourier Transmission Infrared spectrometer (FT-IR) for their near infrared reflectance spectra in wavelength ranging from
2.0 to 4.0 µm [4]. They were also analyzed with a MicrOmega, infrared imager comparable to that onboard instrument of
MASCOT lander released from Hayabusa2 spacecraft, for obtaining overall and local infrared spectra in the bulk Ryugu samples[1, 5-7]. Finally, they were analyzed with an optical microscopic imaging through six filters (ul: 0.39 µm, b: 0.48µm, v: 0.55µm, Na: 0.59 µm, w: 0.70 µm, x: 0.85 µm), compatible with the ONC-T camera of Hayabusa2, onboard instrument of Hayabusa2[8]. After the series of initial descriptions for bulk Ryugu samples, individual particles have been handpicked from the bulk
samples to sapphire dishes for individual samples with a vacuum tweezer, and described in the same manner as the bulk samples
experienced [9-11]. The results of initial descriptions for bulk Ryugu samples are presented in [4]. Their small bulk densities
and dark visible and infrared spectral features indicates that obtained samples are representative of surface materials of Ryugu.
Together with absence of high temperature components like a chondrule and a Calcium-Aluminum rich Inclusion (CAI) andpresence of 2.7 µm absorption band in infrared spectra, which corresponds to hydroxyls (-OH) absorption implying abundantphyllosilicate, they are most similar to CI chondrites among known planetary materials.
Data archive and sample distributions: All the obtained data by the initial descriptions have been archived in Hayabusa2
sample data catalog [12]. This catalog will be in public soon as a reference of Announcement of Opportunity (AO) for Ryugu
samples, which will start in early 2022. Any researcher can apply for the AO, and Ryugu samples will be distributed to Principle
Investigators (PIs) of selected proposals in the middle of 2022.

References: [1] Tsuda Y. et al. (2020) Acta Astron. 171, 42-54. [2] Tachibana S. et al. (2021) LPS, XXXXXII, Abstract #1289.
[3] Yada T. et al. (2021) LPS, XXXXXII, Abstract #2008. [4] Yada T. et al., submitted to Nature Astron. [5] Pilorget C. et al.,submitted to Nature Astron. [6] Bibring J.-P. et al., this meeting. [7] Yogata K. et al., this meeting. [8] Sugita S. et al. (2020)
Science 364, eaaw0422. [9] Miyazaki A. et al., this meeting. [10] Hatakeda K. et al., this meeting. [11] Cho Y. et al., thismeeting. [12] Nishimura M. et al., this meeting.

First NIR hyperspectral imaging of Hayabusa2 returned samples by the MicrOmega microscope within the ISAS Curation Facility
1

Pilorget, C.; 2,3Okada, T.; 1Hamm, V.; 1Brunetto, R.; 2Yada, T.; 1Loizeau, D.; 2Riu, L.; 2,3Usui, T.; 4Moussi-Soffys,
A.; 2,5Hatakeda, K; 2Nakato, A.; 2Yogata, K.; 2,6Abe, M.; 1Aléon-Toppani, A.; 1Carter, J.; 1Chaigneau, M.; 1Crane, B.;1
Gondet, B.; 2,5Kumagai, K.; 1Langevin, Y.; 1Lantz, C.; 1Le Pivert-Jolivet, T.; 1Lequertier, G.; 1Lourit, L.; 2Miyazaki,
A.; 2Nishimura, M.; 1Poulet, F.; 7Arakawa, M.; 8Hirata, N.; 8Kitazato, K.; 2Nakazawa, S.; 9Namiki, N.; 2Saiki, T.;
3
Sugita, S.; 2,3Tachibana, S.; 2,6,10Tanaka, S.; 2,6Yoshikawa, M.; 2,6Tsuda, Y.; 11Watanabe, S.; 1Bibring, J.-P.
[1] Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 91400 Orsay, France, [2] Institute of Space andAstronautical Science, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan, [3] University of Tokyo,
Bunkyo, Tokyo 113-0033, Japan, [4] Centre National d'Etudes Spatiales, 18 Avenue E. Belin, 31401 Toulouse,
France, [5] Marine Works Japan, Ltd., Yokosuka 237-0063, Japan, [6] The Graduate University for Advanced Studies(SOKENDAI), Hayama 240-0193, Japan, [7] Kobe University, Kobe 657-8501, Japan, [8] The University of Aizu,
Aizu-Wakamatsu 965-8580, Japan, [9] National Astronomical Observatory of Japan, Mitaka 181-8588, Japan, [10]University of Tokyo, Kashiwa 277-8561, Japan, [11] Nagoya University, Nagoya 464-8601, Japan.
Introduction: On December 6, 2020, the Hayabusa2 mission successfully returned to Earth ~ 5.4 g of samples collected at the surface of the C-type asteroid Ryugu [1,2]. Its surface was first sampled on February 22, 2019, then on
July 11, 2019, close to a 15-meter large artificial crater, so as to possibly access sub-surface material [3]. The collected
samples are now kept at the Extraterrestrial Samples Curation Center of JAXA at ISAS in Sagamihara, Japan, for a
first round of preliminary analyses, with the objective of characterizing in a non-destructive manner both the bulk
samples and a few hundreds of grains extracted from them [4]. In particular, the goal is 1) to support their further
detailed characterization by the international Initial Analysis Teams, and 2) to build a catalogue of the grains, accessible to the international community through AO selection, starting mid-2022.
Methods: The preliminary characterization of these samples is being conducted with a visible microscope withfive color filters, a FTIR spectrometer operating in the 1-4 µm range, and MicrOmega, a hyperspectral NIR microscope
developed at Institut d'Astrophysique Spatiale (Université Paris-Saclay/CNRS, Orsay, France), operating in the nearinfrared range (0.99-3.65 µm) [5]. This is the first time that preliminary analyses of returned extraterrestrial samples
include a characterization by a NIR hyperspectral microscope.
Results: Preliminary outcomes of the analyses performed with MicrOmega will be presented. In particular, therepresentativity of the samples collected by the Hayabusa2 spacecraft will be addressed through the comparison of
the spectra obtained by MicrOmega and of the NIRS3 remote sensing IR spectrometer [6] which performed a spectral
characterization (1.8-3.2 µm) of Ryugu's surface, including the sites of the samples' collection [7,8].
At a global scale, all bulks exhibit similar features, with a dominant OH- 2.7 µm component and a 3.3 – 3.5 µm
band centered around 3.4 µm. Their variation at different spatial scales and significance will be presented. Specificsignatures, detected in grains typically present in <1% of the pixels, but of high relevance regarding the processes
determining Ryugu formation and evolution, will also be presented and discussed.
References: [1] Binzel R. P. et al. (2002), Physical Properties of Near-Earth Objects. pp. 255-271, [2] Vilas F.
(2008) The Astronomical Journal 135 (4), 1101-1105, [3] Morota et al. (2020) Science 368, Issue 6491, pp. 654-659,[4] Yada T. et al., Nature Astronomy, submitted, [5] Bibring J.-P. et al. (2017) Astrobiology 17, Issue 6-7, pp.621626, [6] Iwata T. et al. (2017) Space Science Reviews 208 (1-4), 317-337, [7] Kitazato K. et al. (2019) Science 364(6437), 272-275, [8] Kitazato K. et al. (2020) Nature Astronomy, Volume 5, p. 246-250.

Initial analysis of Hayabusa2 returned samples from asteroid (162173) Ryugu
Shogo Tachibana1,2, Hisayoshi Yurimoto3, Tomoki Nakamura4, Takaaki Noguchi5,6, Ryuji Okazaki6, Hikaru Yabuta7, Hiroshi
Naraoka6, Kanako Sakamoto2, Sei-ichiro Watanabe8, Yuichi Tsuda2, and the Hayabusa2 Initial Analysis team1
Univ. Tokyo, 2ISAS, JAXA, 3Hokkaido Univ, 4Tohoku Univ., 5Kyushu Univ., 6Kyoto Univ., 7Hiroshima Univ., 8Nagoya Univ.
The JAXA’s Hayabusa2 spacecraft explored C-type near-Earth asteroid (162173) Ryugu from June 2018 to November 2019,
during which two touchdown operations were made to collect surface and subsurface samples. The Hayabusa2 delivered its
reentry capsule on December 6, 2020 to Woomera, South Australia [1]. The sample container inside the reentry capsule was
opened in the clean chamber system dedicated to Ryugu samples at ISAS, JAXA. Dark particles were found in both chambers
A and C, which were used for the storage of the samples collected at the first and second touchdown, respectively. The total
amount of the samples exceeds 5 g, which is much larger than the minimum requirement of 0.1 g [2]. Many millimeter-sizedparticles were present with fine powdery materials, and centimeter-sized grains, close to the maximum obtainable size [3],were found in the chamber C. The color, morphology, and spectroscopic features of the grains indicates that they well
represent the surface materials of Ryugu.
The initial analysis of a fraction of returned samples, led by the Hayabusa2 project, has begun in June 2021 after the
6-month sample description at the ISAS curation facility without exposure to the air. The initial analysis aims at maximizing
the scientific achievement of the project with answering important fundamental questions such as what materials Ryugu
consists of, how Ryugu evolved from its formation to the present, and how similar or different Ryugu samples are to the
known meteorites. The findings from Ryugu samples are expected to invoke cosmochemical discussion on the origin andevolution of the Solar System architecture such as the isotopic dichotomy in the early Solar System, the delivery of water andorganics to the inner Solar System, and the asteroid-comet continuum. The initial analysis also aims at providing the groundtruth for the remote sensing data obtained by the Hayabusa2 spacecraft.
The initial analysis team consists of six sub-teams for 1) chemistry (elements and isotopes) (Lead: Hisayoshi
Yurimoto, Hokkaido University), 2) petrology and mineralogy of coarse grains (mm-sized grains [stone]) (Lead: Tomoki
Nakamura, Tohoku University), 3) petrology and mineralogy of fine grains (<100 μm-sized grains [sand]) (Lead: Takaaki
Noguchi, Kyoto University/Kyushu University), 4) volatiles (Lead: Ryuji Okazaki, Kyushu University), 5) insoluble organic
matter (macromolecular organics) (Lead: Hikaru Yabuta, Hiroshima University), and 6) soluble organic matter (organic
molecules) (Lead: Hiroshi Naraoka, Kyushu University). The total number of teams members is nearly 300 from fourteen
countries. The initial analysis will continue for 12 months. The data obtained during the initial analysis will be archived in the
JAXA curatorial sample database to prove the potential of the samples to the community.
Three hundred milligrams of Ryugu samples (6 % of the total samples by mass) have been allocated from JAXA tothe initial analysis team; Twenty two grains, which were individually photographed, weighed, and spectroscopically examinedin the clean chamber system, and ten aggregate samples that mainly consist of particles smaller than 1 mm in diameter (Table
1).
Table 1. Samples allocated to the Hayabusa2 initial analysis team.
Individual grains
Individual grains
Aggregates
Aggregates(Chamber A)(Chamber C)(Chamber A)(Chamber C)
A0026 3.9 mg
C0002 93.5 mg
A0104 0.3 mg
C0105 0.4 mg
A0040 3.0 mg
C0023 5.0 mg
A0105 4.0 mg
C0106 4.0 mg
A0055 5.9 mg
C0025 5.6 mg
A0106 38.4 mg
C0107 38.8 mg
A0058 3.3 mg
C0033 2.4 mg
A0107 31.0 mg
C0108 33.0 mg
A0063 3.8 mg
C0040 4.9 mg
A0108 3.5 mg
C0109 3.7 mg
A0064 6.7 mg
C0046 2.6 mg
A0067 3.6 mg
C0055 0.8 mg
A0080 1.4 mg
C0057 0.9 mg
A0086 0.9 mg
C0061 1.3 mg
A0089 1.0 mg
C0076 4.7 mg
A0094 1.8 mg
C0103 1.5 mg

The allocated samples have been individually investigated by each sub-team or by collaboration of multiple sub-teams. The
C0002 grain from the chamber C is the third largest particle (~9 x 5 x 4 mm) among all the returned particles (Table 1). Thisgrain has been analyzed by all six sub-teams.
In this presentation we discuss the goals and overall activities of the initial analysis of Ryugu samples. Preliminary
results of elemental and isotopic analyses, mineralogical and petrological observation, and analyses of volatiles and organic
components will be presented from each sub team at the meeting [e.g., 4–22].
References[1] Tachibana S. et al. (2021) 51st LPSC, Abstract #1289. [2] Tachibana S. et al. (2014) Geochem. J. 48, 571–587. [3] Sawada
H. et al. (2017) Space Sci. Rev. 208, 81–106. [4] The Hayabusa2-initial-analysis chemistry team et al. (2021) this meeting. [5]Nakamura T. et al. (2021) this meeting. [6] Noguchi T. et al. (2021) this meeting. [7] Okazaki R. et al. (2021) this meeting. [8]Yabuta H. et al. (2021) this meeting. [9] Naraoka H. et al. (2021) this meeting. [10] Tsuchiyama A. et al. (2021) this meeting.
[11] Dionnet Z. et al. (2021) this meeting. [12] Rubino S. et al. (2021) this meeting. [13] Viennet J.-C. et al. (2021) thismeeting. [14] Matsumoto T. et al. (2021) this meeting. [15] Nishiizumi K. et al. (2021) this meeting. [16] Kebukawa Y. et al.
(2021) this meeting. [17] Bonal L. et al. (2021) this meeting. [18] Stroud R. M. et al. (2021) this meeting. [19] Nittler L. R. etal. (2021) this meeting. [20] Takano Y. et al. (2021) this meeting. [21] Orthous-Daunay F.-R. et al. (2021) this meeting. [22]Schmitt-Kopplin P. et al. (2021) this meeting.

Progress of chemical characterization of asteroid Ryugu samples
The Hayabusa2-initial-analysis chemistry team1,
T. Nakamura , T. Noguchi , R. Okazaki2, H. Yabuta2, H. Naraoka2, K. Sakamoto2, S. Tachibana2, S. Watanabe2 and Y. Tsuda2
2

2

1

2

See end of this abstract
Tohoku Univ., Kyoto Univ., Kyushu Univ., Hiroshima Univ., Kyushu Univ., JAXA, Tokyo Univ., Nagoya Univ. and JAXA

It is believed that meteorites come from asteroids. Samples of asteroid (25143) Itokawa returned by the JAXA Hayabusa
mission revealed that S-type asteroids are composed of materials consistent with the ordinary chondrite class [1, 2]. The JAXA
Hayabusa2 [3] spacecraft launched on December 3rd, 2014 towards an asteroid (162173) Ryugu to clarify relationships
between C-type asteroids and the carbonaceous chondrite class. Remote sensing observations from Hayabusa2 show that (1)the albedo of Ryugu is darker than those of every known meteorite class [4, 5], (2) an absorption band at 2.72 µm indicatesthat phyllosilicates are ubiquitous on Ryugu [5], (3) the strength and shape of the absorption band feature suggests that Ryugu
materials experienced heating above 300 °C [6], and (4) thermal inertia suggests that Ryugu materials are more porous thanevery known carbonaceous chondrite [7]. These results suggest that carbonaceous chondrite class materials are plausible for
Ryugu materials, but no known carbonaceous chondrite completely matches the results obtained from Ryugu.
The Hayabusa2 spacecraft made two successful landings operations onto Ryugu to collect asteroidal materials in 2019and delivered the collected samples to the Earth on December 6th, 2020. The returned samples are detritus from pebbles to clay,
exceeding 5 grams in total. Their colors, shapes and macro-structures are consistent with those of the remote sensing
observations, indicating that the returned samples are representative of the asteroid Ryugu [8]. The initial analysis of the
Ryugu samples began in June 2021. At that time, samples totaling ~125 mg, containing powder and particles from the 1st and2nd touchdown sites, were allocated to the Initial Analysis Chemistry Team.
The goals of the Initial Analysis Chemistry Team analyses are to provide fundamental answers to questions relating to
the provenance of Ryugu samples for in-depth research by international scientists in the future: (i) What are the elemental
abundances of Ryugu? (ii) What are the isotopic compositions of Ryugu? (iii) Does Ryugu consist of primary materials formedin the protosolar disk or secondary materials altered on the parent body? (iv) When were Ryugu materials formed? and (v)What are the relations to known meteoritic samples?
Hydrogen, C and S are analyzed by combination of thermogravimetric analysis coupled with mass spectrometry (TGMS) and by pyrolysis and combustion analyses (EMIA-Step). Major and minor elements are analyzed by X-ray fluorescenceanalysis (XRF) using laboratory X-rays and synchrotron radiation. Trace elements are analyzed by inductively coupled plasma
mass spectrometry (ICP-MS) using calibration curve and isotope dilution methods after acid digestion. We quantify theabundance of 66 elements in Ryugu samples: H, Li, Be, C, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni,
Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,
Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Tl, Pb, Bi, Th, and U. Inorganic and organic element concentrations are also analyzed for H
and C.
For isotope analyses, the Ryugu samples are digested with acids, and the target elements are successively separated byion-exchange column chromatography. We use thermal ionization mass spectrometry (TIMS) and ICP-MS with multicollectors to measure isotope ratios. We determine isotope ratios for chronological systems of Rb-Sr, Sm-Nd, U-Th-Pb, Lu-Hf,
Hf-W, Re-Os, Al-Mg, and Mn-Cr. We also determine stable isotope systematics of Ca, Ti, Cr, Fe, Ni, Sr, Ba, Zr, Mo, Ce, Gd,
Ru and Nd to test isotopic dichotomy in the solar system. Oxygen isotope systematics of Ryugu are measured by laserfluorination isotope-ratio mass-spectrometry (LF-IRMS) for bulk samples and by secondary ion mass spectrometry (SIMS) for
individual components in the samples. The SIMS technique is also applied to the Mn-Cr chronological systematics todetermine ages of aqueous alteration. Surveying for circumstellar and molecular cloud matter is conducted by isotope
microscope and NanoSIMS.
References[1] Yurimoto H. et al. 2011. Science 333: 1116. [2] Nakamura T. et al. 2011. Science 333: 1113. [3] Tachibana S. et al. 2014.
Geochem. J. 48: 571. [4] Kitazato K. et al. 2019. Science 364: 272. [5] Sugita S. 2019. Science 364, eaaw0422. [6] Kitazato K.
et al. 2021. Nature Astronomy 5: 246. [7] Okada T. et al. 2020. Nature 579: 518. [8] Tachibana S. et al. 2021. in review.

The Hayabusa2-initial-analysis chemistry team:
H. Yurimoto1, T. Yokoyama2, K. Nagashima3, I. Nakai4, Y. Abe5, Y. Terada6, S. Komatani7, M. Morita7, K. Ichida7, H.
Homma8, K. Motomura8, K. Yui4, T. Usui9, M. K. Haba2, T. Iizuka10, S. Yoneda11, H. Hidaka12, K. Yamashita13, M. Bizzarro14,
F. Moynier15, M. Schöenbächler16, T. Kleine17, N. Dauphas18, Q-Z. Yin19, M. Wadhwa20, R. J. Walker21, R. W. Carlson22, A.
Bouvier23, Y. Amelin24, L. Qin25, I. Gautam2, R. Fukai9, Y. Masuda2, Y. Hibiya10, A. Ishikawa2, A. Pack26, E. D. Young27, C.
Park28, N. Sakamoto1, W. Fujiya29, N. Kawasaki1, S. Itoh30, K. Terada31, M. Ito32, M. Chaussidon15, J. Aleon33, L. Piani34, S.
Russell35, P. Hoppe36, S. Amari37, K. D. McKeegan27, M-C. Liu27, G. R. Huss3, A. N. Krot3, C. M. O’D. Alexander22, L. R.
Nittler22, A. M. Davis18, A. Nguyen38, N. Kita39, K. Kitajima39, T. R. Ireland40, B-G. Choi41, A-C. Zhang42, K. Bajo1
1

Hokkaodo Univ., 2Tokyo Tech., 3Univ. Hawai‘i, 4Tokyo Univ. Sci. 5Tokyo Denki Univ., 6SPring-8, 7HORIBA TECHINOSERVICE Co., Ltd., 8Rigaku Co., 9JAXA, 10Univ. Tokyo, 11National Museum Nature Sci. Tokyo, 12Nagoya Univ. 13Okayama
Univ., 14Natural History Museum Denmark, 15Inst. Phys. Globe Paris, 16ETH, 17Univ. Münster, 18Univ. Chicago, 19UC Davis,
20
ASU, 21Univ. Maryland, 22Carnegie Inst. Sci., 23Univ. Bayreuth, 24ANU, 25China Univ. Geosci., 26Univ. Göttingen, 27UCLA,28
KOPRI, 29Ibaraki Univ., 30Kyoto Univ., 31Osaka Univ., 32JAMSTEC, 33MNHN, 34CRPG, 35NHM, 36MPI Chemistry,
37
Washington Univ. St. Louis, 38NASA, 39Univ. Wisconsin, 40Univ. Queensland, 41SNU, 42Nanjing Univ.

Initial analysis of “stone” size Ryugu samples: current status
Tomoki Nakamura1, Megumi Matsumoto1, Kana Amano1, Yuma Enokido1, Mike Zolensky2, Takashi Mikouchi3, Yuri Fujioka1,
Mizuha Kikuiri1, Eiichi Kagawa1, Daisuke Nakashima1, Adrian Brearley4, Mikhail Zolotov5, Akira Tsuchiyama6, Masayuki
Uesugi7, Yoshio Takahashi3, Moe Matsuoka8, Ralph Milliken9, Donald Brownlee10, David Joswiak10, Miki Takahashi1,
Kazuhiko Ninomiya11, Tadayuki Takahashi3, Takahito Osawa12, Kentaro Terada11, Frank E. Brenker13, Beverley Tkalcec13,
Yuki Kimura14, Satoshi Tanaka8, Housei Nagano15, Rosario Brunetto16, Alice Aléon-Toppani16, Queenie Chan17, Mathieu
Roskosz18, Esen Ercan Alp19, Pierre Beck20, Aiko Nakato8, Takaaki Noguchi21, Masahiko Tanaka22, Takahiro Hiroi9, Eri
Tatsumi23, Faith Vilas24, Amanda R. Hendrix24, Camilo Jaramillo25, Gerardo Dominguez26, Cecile Engrand16, Jean Duprat16,
Hidenori Genda27, Kousuke Kurosawa28, Sara Russell29, Ashley King29, Enrica Bonato30, Chi Ma31, Kentaro Uesugi7, Akihisa
Takeuchi7, Jyunya Matsuno21, Akira Miyake21, Satomi Enju32, Masahiro Yasutake7, Toru Matsumoto33, Shota Okumura21, Aki
Takigawa3, Shohei Yamashita34, Takahiro Kawai3, Jean-Christophe Viennet18, Barbara Lavina19, Toshiaki Tanigaki35, Kazuo
Yamamoto36, Deborah Domingue Lorin24, Ferenc Borondics37, Zélia Dionnet16, Donia Baklouti16, Zahia Djouadi16, Cateline
Lantz16, Stefano Rubino16, Laszlo Vincze38, Bart Vekemans38, Gerald Falkenberg39, Pieter Tack38, Ella De Pauw38, Miles
Lindner13, Benjamin Bazi38, Shinya Yamada40, Kenya Kubo41, Shunsaku Nagasawa3, Taiga Wada1, Satoshi Takeshita34,
Akihiro Taniguchi21, Shin Watanabe3, 8, Izumi Umegaki34, Chiu I-Huan11, Yasuhiro Miyake34, Kosuke Inoue42, Seiji Sugita3,
Kohei Kitasato43, Hisayoshi Yurimoto14, Ryuji Okazaki33, Hikaru Yabuta44, Hiroshi Naraoka33, Kanako Sakamoto8, Shogo
Tachibana3,8, Seiichiro Watanabe15, Yuichi Tsuda8 and the Hayabusa2-initial-analysis Stone team.
1Tohoku University, Japan, 2NASA/JSC, USA, 3The University of Tokyo, Japan, 4University of New Mexico, USA, 5Arizona State University,

USA, 6Ritsumeikan University, Japan and CAS, GIG, China, 7JASRI/SPring-8, Japan, 8ISAS/JAXA, Japan, 9Brown University, USA,
10University of Washington, USA, 11Osaka University, Japan, 12Japan Atomic Energy Agency, Japan, 13Goethe University Frankfurt,
Germany, 14Hokkaido University, Japan, 15Nagoya University, Japan, 16University of Paris-Saclay, France, 17University of London, UK,
18Muséum National d'Histoire Naturelle, France, 19Argonne National Laboratory, USA, 20Université Grenoble Alpes, France, 21Kyoto
University, Japan, 22National Institute for Materials Science, Japan. 23 Instituto de Astrofísica de Canarias, Spain,, 24Planetary Science
Institute, USA, 25Pensylvania State University, 26Callfornia State University, USA, 27Tokyo tech, Japan, 28Chiba tech, Japan, 29Natural
History Museum, UK, 30Deutsches Zentrum für Luft- und Raumfahrt, Germany, 31Caltech, USA, 32Ehime University, Japan, 33Kyusyu
University, Japan, 34High Energy Accelerator Research Organization (KEK), Japan, 35Hitachi, Ltd., Japan, 36Japan Fine Ceramics
Center, Japan, 37SOLEIL Synchrotron, France, 38Ghent University, Belgium, 39DESY, Germany, 40Rikkyo University, Japan,
41International Christian University, Japan, 42Kanazawa University 43University of Aizu, Japan, 44Hiroshima University, Japan.

As a part of the initial analysis of the Ryugu samples, we perform a variety of analyses of millimeter-sized "stones". Our
goals are to elucidate the entire formation process of Cb-type asteroid Ryugu from the viewpoint of petrology and mineralogy
and obtain necessary information by sample analysis, and then simulate the formation of Ryugu based on the evidence
obtained from sample analysis. Eighteen stones (8 from the chamber A and 10 from the chamber C) were received from the
ISAS curation facility on June 1, 2021, and placed into a fully nitrogen-displaced glove box at Tohoku University. At the sametime, we also received the powder samples from the chamber A and the chamber C. All the allocated samples were put in thesample transport containers prepared by ISAS in the nitrogen atmosphere inside the clean chamber system dedicated to Ryugu
samples. The containers were then transferred to the nitrogen glovebox at ISAS, where all the containers were completely
sealed in plastic bags with moisture and oxygen absorbers. No moisture or oxygen was detected when the bags were opened in
the glove box at Tohoku University, so it was confirmed that there was no exposure to the atmosphere during transport.
To date, a number of analyses have been carried out successfully and within schedule margins. The analysis started with themeasurement of reflectance spectra, which are sensitive to atmospheric oxidation, hydroxylation, and adsorbed water. The
ultraviolet, visible, near-infrared, and mid-infrared reflectance spectra were measured while the samples were kept airtight.
The spectra of powder samples and stone samples (as aggregates and as a single stone) were successfully obtained. Concurrent
with the analyses described below were ultra-violet spectral observations on stone samples, also transported and performed in
an inert environment, conducted at the University of Illinois Urbana-Champaign (USA).
A major feature of the stone team's analysis is the use of synchrotron radiation facilities around the world. Since thisanalysis is non-destructive, stone samples whose reflectance spectra were measured were sent to KEK, SPring-8, ESRF
(France), SOLEIL (France), DESY (Germany), and APS (USA). Using these synchrotron radiation facilities, high spatial
resolution and sensitivity XRD, STXM, XANES, CT [1], IR-CT, FT-IR [2, 3], XRF, and Mössbauer [4] analyses were
performed. Most of the analyses were carried out under airtight conditions on the stone samples and the particulates separated
from the stone samples. These analyses allowed us to determine the three-dimensional distribution of solid phases andelements, redox state, density, and porosity of the stone samples.
Furthermore, as a characteristic analysis of the stone team, light elemental analysis using negative Muon was performed at the
MLF facility of J-PARC with an exceptionally long allocation of machine time. This is the non-destructive method to measure
the concentration of light elements in the whole (not the surface) of stone samples. Because the characteristic X-rays produced

by muon irradiation are much higher in energy than the fluorescent X-rays produced by X-ray irradiation, there is little effectof self-absorption by the sample, and therefore, the concentration of light elements such as carbon, oxygen, and sodium in theentire "stone" sample can be determined.
Some stone samples are currently being measured for thermal conductivity and strengths in order to understand the physicalproperties of asteroid Ryugu. The data obtained from these measurements are useful for interpreting the remote-sensing data
data taken from the surface layer of the asteroid Ryugu [5-8]. It is also important for understanding the behavior of the Ryugu
material during impact events.
The surfaces of many stone samples were observed by electron microscopy and other techniques, especially on natural “flat”
surfaces formed on 5 stones. As a result, characteristric mineral aggregates formed by the reactions with water andcharacteristic impact features were observed on some samples. Based on the observations of surfaces and the synchrotron
measurements of the whole stones, important objects such as characteristic structures and specific crystal aggregates forunderstanding the formation history of the asteroid were identified, and these parts were separated from the stone samples
using a Xe beam (pFIB) and analyzed by various methods including transmission electron microscopy and synchrotron
radiation analysis. Many stone samples, from which important objects have been separated, are embedded in epoxy resin andcut to produce many polished sections. Electron microscopy and spectroscopic measurements of the polished surfaces arebeing carried out to reveal the detailed mineralogical properties and elemental distribution inside the stone samples. In this fall,
the allocate beam time for synchrotron radiation will begin, and we plan to analyze single crystals and characteristic objects
separated from the stone samples. Photometric measurements in the ultra-violet and visible to near-infrared will also be madethis fall on the powders produced in the structural experiments to facilitate comparisons with the ONC-T and NIRS3 remotesensing observations.
Acknowledgement
We thank Drs. H. Nakao (KEK), K. Nitta (JASRI/SPring-8), O. Sekizawa (JASRI/SPring-8) for support in synchrotron
analysis and Dr. O. Sasaki for support in CT analysis at Tohoku University.
References[1] Tsuchiyama A. et al. in this volume. [2] Dionnet Z. et al. in this volume.[3] Rubino S. et al. in this volume. [4] Viennet J-C.
et al. in this volume [5] Watanabe S. et al. 2019. Science 364:268.[6] Sugita S. et al. 2019. Science 364:252. [7] Kitazato K. et
al. 2019. Science 364:272. [8] Okada T. et al. 2020. Nature 579:518.

Mineralogy and surface modification of small grains recovered from the asteroid 162173 Ryugu
T. Noguchi1, T. Matsumoto1, A. Miyake1, Y. Igami1, M. Haruta1, H. Saito2, S. Hata2, Y. Seto3, M. Miyahara4, N. Tomioka5, H.
A. Ishii6, J. P. Bradley6, K. Ohtaki6, E. Dobrică6, T. Nakamura7, M. Matsumoto7, A. Tsuchiyama8, 9; M. Yasutake10, J.
Matsuno8, S. Okumura1, K. Uesugi10, M. Uesugi10, A. Takeuchi10, M. Sun9, S. Enju11, A. Takigawa12, H. Leroux13, C. Le
Guillou13, D. Jacob13, M. Marinova13, F. de la Peña13, F. Langenhorst14, D. Harries14, P. Beck15, T. H. V. Phan15, R. Rebois15,
N. M. Abreu16, T. Zega17, P.-M. Zanetta17, M. Thompson18, M. Lee19, L. Daly19, P. A. Bland20, R. Stroud21, K. Burgess21, J. C.
Bridges22, L. Hicks22, M. E. Zolensky23, D. R. Frank6, J. Martinez24, H. Yurimoto25, K. Nagashima6, N. Kawasaki25, R.
Okazaki2, H. Yabuta4, H. Naraoka2, K. Sakamoto26, S. Tachibana12, S. Watanabe27, Y. Tsuda26, and the Hayabusa2 Initial
Analysis Team1
2
3
Kyoto Univ., Japan; Kyushu Univ., Japan; Kobe Univ., Japan; 4Hiroshima Univ., Japan; 5Kochi Core
Center, JAMSTEC, Japan; 6Univ. of Hawaii, USA; 7Tohoku Univ., Japan; 8Ritsumeikan Univ., Japan; 9Guangzhou Instituteof Geochemistry, China; 10JASRI, Japan; 11Ehime Univ., Japan; 12Univ. of Tokyo, Japan; 13Univ. de Lille, France; 14Univ. ofJena, Germany; 15Univ. Grenoble Alpes, France; 16Penn State, USA; 17Univ. of Arizona, USA; 18Purdue Univ., USA; 19Univ. of
Glasgow, UK; 20Curtin Univ., Australia; 21US Naval Research Laboratory, USA; 22Univ. of Leicester, UK; 23JSC/NASA, USA;
24
Jacobs Engineering, USA, 25Hokkaido Univ., Japan; 26JAXA/ISAS, Japan; 27Nagoya Univ., Japan
Introduction: Surface material on airless bodies exposed to the interplanetary space experienced the bombardment by lowenergy (~1 keV/nucleon) solar wind particles and micrometeoroid impacts. These processes, alongside the resultant surface
modifications, and spectral darkening and reddening are called space weathering [1]. Space weathering of the Moon and theasteroid 25143 Itokawa belonging to S-type asteroids have been investigated intensively [e.g. 1-5]. The Hayabusa 2 spacecraft
returned samples from the asteroid 162173 Ryugu C-type asteroid. The Ryugu samples give us the first opportunity toinvestigate space weathering of C-type asteroids. The Mineralogy-Petrology Fine (M-P F or Sand) sub-team mainly
investigates small grains (typically ~100 µm across). The main purposes of the M-P F sub-team are to understand the variationof mineralogy of the allocated grains and the nature of space weathering of the asteroid Ryugu. The M-P F sub-team iscomprised of 51 members belonging to 25 universities and laboratories.
Sample and methods: Numerous small Ryugu grains, ~100 µm across on average, were allocated to the M-P F sub-team.
Surface morphology of >350 grains from the chamber A of the sample canister have been observed by JEOL JSM-7001F fieldemission scanning electron microscope (FE-SEM) at Kyoto Univ. and by Thermo Scios focused ion beam (FIB)-SEM at
Kyushu Univ. Elemental mapping analysis was also performed using Energy dispersive spectrometer (EDS) equipped on the
FE-SEM. Most of the grains were attached to Au plates with small amounts of epoxy glue in N2 filled glove box for SEM
observation. Some grains were just placed on Pt plates without using any glue to make FIB sections in response to requests
from some members. One sample was prepared by Reichelt Ultracut ultramicrotome at Kyoto Univ. In addition to the small
grains, the Chemistry sub-team loaned a polished sample of a fragment originating from a large grain A0026 (~3 mm wide)
because the sample has a bubble-rich material on its surface. Seven samples were able to be prepared for the detailed analysis.
Up to now we have prepared ~80 FIB sections from 40 grains and >30 FIB sections have already been distributed to themembers. To understand mineralogy and petrology down to the nanometer of these grains and to clarify the detailed
mineralogical analyses of space weathering of the C-type asteroid Ryugu, we are now performing (scanning) transmission
electron microscopy ((S)TEM), synchrotron radiation X-ray absorption fine structure (XANES and EXAFS) analysis, nanotomography, and atom probe analysis at 15 universities and laboratories.
Results: Major minerals of the small Ryugu grains are phyllosilicates (saponite and serpentine), Fe-bearing sulfides, magnetite,
dolomite, and a lesser amount of breunnerite. It is obvious that the asteroid Ryugu experienced severe aqueous alteration anddid not experience heating enough to make secondary anhydrous minerals such as olivine, pyroxene and Fe metal, which arecommon in severely heated carbonaceous chondrites. Serpentine in these Ryugu grains may have better crystallinity than thatin Orgueil and Ivuna CI chondrites [e.g., 6]. Typical spacing of (001) of saponite is ~1.0-1.3 nm, which suggests partial
dehydration of interlayer H2O molecules. Minor minerals so for observed are hydroxyapatite, ilmenite, magnesiochromite,
manganochromite, Cr oxide, Cu-bearing ZnS, (Fe, Ni)2P, FeCr2S4, cubanite, Na- and Mg-bearing phosphate, forsteritic olivine,
and Fe-free low-Ca pigeonite. A moissanite crystal was also identified, which could be a presolar grain.
The surfaces of the most Ryugu grains investigated have highly euhedral pyrrhotite crystals. Their surfaces preserve quite
sharp steps, which may reflect growth or dissolution in aqueous solutions. Magnetite crystals that form framboidal aggregateshave shapes as rounded as those in Orgueil and Ivuna. In addition, some magnetite crystals have facets as sharp as those inTagish Lake C ungrouped meteorite. The presence of these Fe sulfide and oxide suggests that these surfaces did not experienceenough exposure to the interplanetary space to degrade the surfaces of these minerals.
After scrutinizing >350 small Ryugu grains by FE-SEM and FIB-SEM, we found 10 small Ryugu grains having obviously
different surface morphology. Figure 1 shows an example of such grains with abundant open bubbles. The bubble-rich surfaces
form a continuous layer containing abundant bubbles. In Fig. 1(b), the bubble walls are as thick as ~0.5 µm at the thickest
places. Most bubble-rich layers have ~50 - ~500 nm thick, but the layer of A0026 has up to ~3 µm thick. The bubble-rich layer
in Fig. 1(b) is amorphous and contains abundant tiny Fe sulfide crystals based on selected area electron diffraction (SAED)
patterns and electron diffraction mapping. Preliminary analysis of energy-loss near-edge structures of Fe L2, 3 edge of the
bubble-rich layer and the subsurface phyllosilicate suggests that the former is much more enriched in Fe2+ than the latter. Moredetailed description of the rugged Fe sulfide and the other phases will be presented in another presentation [7].

Fig. 1 Secondary electron and annular dark-field images of a small Ryugu grain with a bubble-rich surface. (a) The surface iscovered by a gently rolling layer with abundant open bubbles. Abundant bright tiny speckles are on the surface. (b) A crosssection of the bubble-rich layer and the interior. Abbreviations: Po: pyrrhotite; Phy: phyllosilicate; depo: deposition.
Discussion and conclusion: These major minerals and the petrography of the small Ryugu grains indicate that the asteroid
Ryugu experienced severe aqueous alteration that can be classified as C1. The mineralogy and petrology of these grains are
similar to CI chondrites but these grains lack ferrihydrite and sulfates, both common among CI chondrites [e.g., 6, 8 andreferences therein]. The formation of ferrihydrite and sulfates may have occurred by terrestrial weathering. The spacing of(001) of saponite increased to ~1.3 nm on average by using ethylene glycol as the trough liquid during ultramicrotomy, whichmeans that saponite in the Ryugu samples can rehydrate.
Morphology of the bubble-rich layers is apparently similar to melt sheets (Fig. 1a). However, it does not necessarily mean that
all the layers were formed through melting by meteoroid impacts. The formation of similar bubble-rich amorphous layers by
H+ or He+ ion irradiation has already been reported [9-11]. Although the size and number density of bubbles in the amorphouslayer are different from the irradiation experiments and the natural samples, the difference can be interpreted by the different
fluxes between them. Therefore, we believe that at least thin bubble-rich layers were related to solar wind irradiation. Unlike
the irradiation experiments, the bubble-rich layer in Fig. 1(b) is more enriched in Fe, S, and Ca than the subsurfacephyllosilicate. Recondensation of elements derived from the surrounding phases may have also played a role in thecompositional difference. Because the thickness of the bubble containing layer is quite variable, the relative contribution ofirradiation and micrometeoroid impacts that resulted in vaporization and recondensation of elements may be quite different atplaces. The M-P F sub-team continues to assess the role of recondensation in the space weathering of the Ryugu C-type
asteroid. Although small Ryugu grains with the space weathering rims are quite rare among the investigated samples, it does
not necessarily mean that such grains are rare on the surface of Ryugu because most of the surfaces are exposed to theinterplanetary space may have been destroyed during the sampling sequence using Ta projectiles. If most of the space exposed
surface had the bubble-rich amorphous layer on Ryugu, the bubble-rich amorphous surface layers might have affected thereflectance spectra of the asteroid Ryugu.
References [1] Noguchi T. et al. 2011. Science 333, 1121-1125. [2] Noguchi T. et al. 2014. Meteorit. Planet. Sci. 49, 188-214.
[3] Matsumoto T. et al. 2015 Icarus 257, 230-238. [4] Thompson, M. et al. 2014. Earth Planet. Space 66, 89. [5] Burgess K.D.
and Stroud K.D. 2018. J. Geophys. Res. Planets 123, 2022-2037. [6] Tomeoka K. and Buseck P. 1985 Geochim. Cosmochim.
Acta 52, 1627-1640. [7] Matsumoto T. et al. this symposium. [8] Brearley A. and Jones R. 1998. Planetary Materials, pp. C1.
[9] Thompson M. et al. 2020. Icarus 346, 113775. [10] Laczniak D.L. et al. 2020. Icarus 364, 114479. [11] Noguchi T. et al.
2017. Hayabusa 2017 Symp. & 8th Symp. Pol. Sci. (abstract).

Initial Analysis of Volatile Components in the Hayabusa2 Samples
Ryuji Okazaki1, Bernard Marty2, Henner Busemann3, Yayoi N. Miura4, Keita Yamada5, Saburo Sakai6, Ko Hashizume7, Kenichi Bajo8, Shun Sekimoto9, Fumio Kitajima1, Kevin Righter10, Alex Meshik11, Jamie Gilmour12, Naoyoshi Iwata13, Evelyn
Füri2, Sarah Crowther12, Naoki Shirai14, Mitsuru Ebihara15, Yoshinori Takano6, Akizumi Ishida16, Reika Yokochi17, Olga
Pravdivseva11, Jisun Park18, 19, Toru Yada20, Kunihiko Nishiizumi21, Keisuke Nagao22, Jong Ik Lee22, Michael Broadley2,
David Byrne2, My Riebe3, Patricia Clay12, Akihiro Kano4, Marc Caffee23, Shinsuke Kawagucci6, Yohei Matsui6, Ryu
Uemura24, Makoto Inagaki9, Daniela Krietsch3, Colin Maden3, Mizuki Yamamoto1, Hisayoshi Yurimoto8, Tomoki
Nakamura16, Takaaki Noguchi9, Hiroshi Naraoka1, Hikaru Yabuta25, Kanako Sakamoto20, Shogo Tachibana4, 20, Sei-ichiro
Watanabe24 and Yuichi Tsuda20
1

Kyushu Univ., 2CRPG, 3ETH, 4Univ. of Tokyo., 5Tokyo Inst. Tech., 6JAMSTEC, 7Ibaraki Univ., 8Hokkaido Univ., 9Kyoto U.,
10NASA JSC, 11Washington Univ., 12Univ. Manchester, 13Yamagata Univ., 14Tokyo Metro., 15Waseda Univ., 16Tohoku Univ.,
17
Chicago Univ., 18Kingsborough Comm. Coll., ,19AMNH, 20JAXA, 21UC Berkeley, 22KOPRI, 23Purdue Univ., 24Nagoya Univ.,
25
Hiroshima Univ.

The major objectives of the Hayabusa2-initial-analysis volatile team are (1) to determine the pristine volatile components inthe parental materials of the returned Ryugu samples, and (2) to elucidate the origin and chronological history of the asteroid
Ryugu, as well as the evolution of the solar system through determination of volatile carrier phases and abundances of volatilecomponents (e.g., presolar grain abundances). Our analytical data will be linked with remote sensing (NIRS3, ONCs, TIR, and
LIDAR) data and theoretical modeling [e.g., 1-5]. For example, the erosion rate and the degree of gardening of the surface layerof the asteroid Ryugu can be estimated based on trapped solar wind (SW) and cosmic ray produced (cosmogenic) nuclides,
which will be discussed in conjunction with the results based on the remote sensing data [3-5]. Taken together, these will provide
characteristics of the surface materials, such as the degree and duration of the alteration by SW/cosmic ray irradiation andmicrometeorite bombardments.
Our analytical plan for the Ryugu samples consists of three approaches (Fig. 1): One is analyses of native volatiles in the
Ryugu samples which have been treated WITHOUT air-exposure throughout the whole process, since the collection from theasteroid Ryugu to the gas extraction in the laboratories. The goal of this work is to quantify the indigenous compositions with as
minimal terrestrial (atmospheric, biological, and unintentional man-made pollution) contamination as possible. We will obtain

Figure 1.

Analytical flow of the volatile team of the Hayabusa2 initial analysis.

the abundances and isotopic compositions of nitrogen, noble gases, and volatile elements (e.g., H and C in H2, CO, and CO2,methane, and ethane).
The second approach is analyses of the neutron-irradiated samples to determine the Ar-Ar and I-Xe ages and halogen
abundances by noble gas isotope measurements at U. Manchester and Kyushu U., and to obtain abundances of minor/traceelements (e.g., Co, Ni, and Ir) by neutron activation analysis (NAA) at KURNS. Prior to neutron-irradiation, nanoSIMS analysis
will be carried out at AORI on the same samples that are used for the Ar-Ar/I-Xe/halogen analysis at Kyushu U. to understandthe distribution and isotopic compositions of volatile elements (H, C, N, and O).
The third approach is measurements of cosmogenic long-lived nuclides and noble gas isotopes, which are performed for
different samples prepared under an atmospheric environment. The preliminary result of cosmogenic nuclides is reported by [6].
Most of Hayabusa2 samples allocated to the volatile team have been transported to Kyushu Univ. from JAXA, and locatedin a N2 glove box installed at Kyushu Univ., and pelletized without air-exposure in June 2021, except for two particles for thevolatile element analysis at TITECH/JAMSTEC and five samples for cosmogenic nuclides which were directly allocated toBerkeley U. from JAXA. Twenty four pellets have been prepared (Fig. 2), and sent back to JAXA to perform FTIR and FESEM
observations. After these observations, 16 out of 24 samples have been distributed to our team laboratories, ETH, U. Manchester,
Washington U., CNRS-Nancy, Ibaraki U., TITECH/JAMSTEC, and Kyushu U. to measure native volatile compositions. Before
analysis, we measured the sample weight without air-exposure by using a small weighing container (Fig. 3). These careful
operations enable us to obtain the most intact, fresh volatile compositions of the asteroid Ryugu.

Figure 2. The Hayabusa2 samples pelletized onto a Cu disk without air-exposure (2a). The
Cu disk is installed in a metal holder for NanoSIMS analysis and transportation. Enlarged
view of the sample is shown in Fig. 2b.
Figure 3. The small weighing
container developed for the
Hayabusa2 initial analysis.

The remainder of the samples, six pellets have been transported to Tohoku U. and coated with Os and Pt as an antistatic
treatment. These samples have now been exposed to the atmosphere. After coating, the 6 samples were shipped to AORI andinvestigate with NanoSIMS in August 2021. The result of the nanoSIMS analysis will be reported by Drs. Hashizume andIshida somewhere else.
Following NanoSIMS analysis, the 6 pellet samples were transported to Kyushu U. for installation in diamond container
for the NAA. The neutron irradiation and NAA are scheduled to be completed in October. After the NAA, the 6 samples will
be analyzed for Ar-Ar age dating. For I-Xe dating and halogen analysis, two other pellet samples, different from the 6 samples
that have been analyzed for nanoSIMS and NAA, have been distributed to U. Manchester in July. Now all of these preparatory
steps are over and the Ryugu samples are ready for the experiments. We believe that all analyses will proceed successfully.
References[1] Sugita S. et al. 2019. Science 364, eaaw0422 1-11. [2] Kitazato K. et al. 2019. Science 364, 272-275. [3] Tatsumi E. et al.
2021. Nature Astronomy doi.org/10.1038/s41550-020-1179-z. [4] Morota T. et al. 2020. Science 368, 654–659. [5] Tachibana
S. et al. 2021. in review. [6] Nishiizumi K. et al. 2021. This issue.

An initial look at the distributions and compositions of organic macromoleculesin the asteroid Ryugu samples
Hikaru Yabuta1, George Cody2, Cecile Engrand3, Yoko Kebukawa4, Bradley De Gregorio5, Lydie Bonal6, Laurent Remusat7,
Rhonda Stroud5, Eric Quirico6, Larry Nittler2, Minako Hashiguchi8, Mutsumi Komatsu9, Taiga Okumura10, Yoshio Takahashi10,
Yasuo Takeichi11, Emmanuel Dartois3, Jean Duprat7, Jeremie Mathurin3, David Kilcoyne12, Zita Martins13, Scott Sandford14,
Shohei Yamashita11, Ariane Deniset3, Alexandre Dazzi3, Yusuke Tamenori15, Takuji Ohigashi16, Hiroki Suga15, Daisuke
Wakabayashi11, Maximilien Verdier-Paoletti7, Smail Mostefaoui7, Gilles Montagnac17, Jens Barosch2, Kanami Kamide1, Miho
Shigenaka1, Laure Bejach3, Takaaki Noguchi18, Hisayoshi Yurimoto19, Tomoki Nakamura20, Ryuji Okazaki21, Hiroshi
Naraoka21, Kanako Sakamoto22, Shogo Tachibana10, 22, Sei-ichiro Watanabe8, and Yuichi Tsuda22
1

Hiroshima Univ., 2Carnegie Institution of Washington, 3Université Paris Sud, 4Yokohama National Univ., 5Naval ResearchLaboratory, 6Université Grenoble Alpes, 7Muséum national d'Histoire naturelle, 8Nagoya Univ., 9The Graduate Univ. for
Advanced Studies (Sokendai)., 10Univ. of Tokyo, 11High Energy Accelerator Research Organization, 12Advanced Light Source,
13
Universidade de Lisboa, 14NASA Ames Research Center, 15SPring8, 16UVSOR, IMS, 17ENS de Lyon, 18Kyoto Univ.,
19
Hokkaido Univ., 20Tohoku Univ., 21Kyushu Univ., 22JAXA
Hayabusa2 is JAXA’s asteroid sample return mission that targeted the carbonaceous (C-type) asteroid (162173) Ryugu.
The mission aims to unveil the origin and evolution of organic compounds and water in the early Solar System as life’sbuilding blocks [1]. Following the arrival of the Hayabusa2 spacecraft at Ryugu on June 27, 2018, observations by onboard
remote sensing instruments revealed that Ryugu is a top-shaped asteroid with a very low geometric albedo [2-4] and that its
surface is probably partially dehydrated [5]. The Mobile Asteroid Surface Scout (MASCOT) lander observed two types ofboulders on the surface of Ryugu: one type was dark and cauliflower-like with a similar morphology to primitive carbonaceouschondrites, and another type was bright and smooth [6]. The lander’s radiometer revealed that Ryugu has low thermal
conductivity and high porosity unlike any chondritic meteorites, while these thermal properties have similar values to comets[7]. Thanks to the formation of the artificial crater on Ryugu’s surface by a small carry-on impactor [8], two successful
touchdowns on February 22 and July 11, 2019 have enabled collections of samples from two distinct locations on the asteroid,
providing an advantage for investigating the origin and evolution of the Solar System as well as the surface processes of theasteroid. After the sample return on December 6, 2020, the curatorial work on the Ryugu sample has been conducted at JAXA
for the first 6 months [9]. With the significant guidance from the observations and curation, the initial sample analysis has a
one-year mission from June 2021 to June 2022 to address the question of what kind of asteroid Ryugu is.
Organic compounds are a major component of interstellar dust as along with silicates and water ice due to the highabundances of their elements (C, H, O, N, S, P) in the Galaxy. The initial molecular inventory of the Solar System, inheritedfrom the parental molecular cloud, was modified and new complex molecules formed through a variety of processes in the
protoplanetary disk and planetesimals, which resulted in the diverse compositions of asteroids and comets. These small bodies
are thought to have contributed to the formation of our habitable planet, through exogenous delivery of organics and water as
life’s building blocks to the early Earth.
Organic macromolecules from chondritic meteorites have been often characterized as a dark, complex, acid-insolubleorganic matter (IOM). IOM accounts for a major portion of total organic carbon in primitive carbonaceous chondrites (CCs).
The intact chemical structure of IOM in CCs is still unknown, although a number of previous studies have suggested that it iscomposed of aromatic network crosslinking with short-branched aliphatic chains and various oxygen-bearing functionalgroups [10, 11]. Whether IOM was formed in interstellar cloud [12], outer solar nebula [13] or planetesimals [14], is still under
debate. Nevertheless, elemental, molecular and isotopic variations of IOM from various types of small body materials, such as
chondritic meteorites [15-20], interplanetary dust particles (IDPs) [21], cometary dusts [21-23], and Antarctic micrometeorites(AMMs) [24-27], have enabled our comprehensive understanding of chemical history of the early Solar System.
The Hayabusa2-initial-analysis IOM team consists of 36 members from Japan, USA, France, and Portugal. The scientificgoals of IOM team include: i) Decoding the chemical relationship(s) between organics and minerals on a C-type asteroid
parent body, ii) Elucidating formation pathways of organic macromolecules in a C-type asteroid, iii) Determining the origin(s)of organics in a C-type asteroid, iv) Investigating the asteroid-comet continuum, v) better understanding Solar Systemformation and volatile delivery, and vi) Understanding the role of organic macromolecules in the origin of life. In order toaccomplish the goals, we aim to unveil the elemental, isotopic, and functional group compositions, structures and textures oforganic macromolecules from the Ryugu samples. The analytical procedures are configured by combination of micro-Fourier

Transform Infrared Spectroscopy (FTIR), micro-Raman spectroscopy, synchrotron-based scanning transmission x-ray
microscope (STXM), Scanning Transmission Electron Microscopy (STEM) coupled with Electron Energy Loss Spectroscopy(EELS) and Energy Dispersive X-ray Spectroscopy (EDS), Atomic Force Microscope based Infrared Spectroscopy (AFM-IR),and nano-secondary ion mass spectrometry (NanoSIMS). The analytical procedures are applied to the intact Ryugu samples
and the IOM isolated by HCl/HF treatment of the Ryugu samples, respectively.
For the first measurements, Chamber A aggregates (A0108) collected upon the first touchdown and Chamber C aggregates(C0109) collected upon the second touchdown have been analyzed. The individual particles from A0108 and C0109 range
from 200 to 900 μm in size. Some of the particles were crushed on a diamond window for micro-FTIR, micro-Raman, andNanoSIMS. Slices of other particles were prepared with a focused ion beam workstation (FIB) and/or an ultramicrotome toobtain ultra-thin sections for STXM, STEM-EELS, AFM-IR and NanoSIMS. The water/solvent/HCl extraction residues ofother aggregates of Chamber A (A0106) and Chamber C (C0107), which were transferred by SOM team, were treated with 6N
HCl and 1N HCl/9N HF to yield IOM for future measurements.
Organic macromolecules have been identified from the Ryugu samples by all the analytical techniques. The organic
macromolecules were associated with secondary minerals formed through aqueous alteration [28], and they often exhibited D
and/or 15N-rich regions [29, 30]. These results show that the observed organics are of extraterrestrial origin. The FTIR [31] andRaman [32] spectroscopic features as well as the isotopic features [29, 30] of organic macromolecules from the Ryugu samples
were comparable with those of the primitive carbonaceous CI/CM chondrites, while the other features were not necessarily
consistent with the typical CI/CM, demonstrating that Ryugu samples record heterogeneous chemical history in a pristine state[28, 29].

References[1] Tachibana et al. 2014. Geochem. J. 48:571. [2] Watanabe et al. 2019. Science 364:268. [3] Sugita et al. 2019. Science 364:
eaaw0422. [4] Tatsumi et al. 2020 A&A, 639:A83. [5] Kitazato et al. 2019. Science 364:272. [6] Jaumann et al. 2019. Science
365:817. [7] Grott et al. 2019. Nature Astronomy 3:971. [8] Arakawa et al. 2020. Science 368:67. [9] Yada et al. et al. 2021.
under review. [10] Glavin et al. 2018. In: Primitive Meteorites and Asteroids: Physical, Chemical and Spectroscopic
Observations Paving the Way to Exploration (Ed. Abreu N.) pp. 205-271. [11] Martins et al. 2020. Space Sci. Rev. 216:54.
[12] Alexander et al. 2007. GCA 71:4380. [13] Remusat et al. 2010. Astrophys. J., 713:1048. [14] Kebukawa et al. 2013.
Astrophys. J. 771:19. [15] Cody and Alexander, 2005. GCA 69:1085. [16] Yabuta et al. 2005. GCA 40:779. [17] Bonal et al.
2006. GCA 70:1849. [18] Cody et al. 2008. Earth Planet. Sci. Lett. 272:446. [19] Kebukawa et al. 2011. GCA 75:3530. [20]Quirico et al. 2018. GCA 241:17. [18] Messenger, 2000. Nature 404:968. [21] Sandford et al. 2006. Science 314:1720. [22]
Cody et al. 2008. MAPS 43:353. [23] De Gregorio et al. 2011. MAPS 46:1376. [24] Duprat et al. 2010. Science 328:742. [25]Yabuta et al. 2017. GCA 214:172. [26] Noguchi et al. 2017. GCA 208:119. [27] Mathurin et al. 2019. A&A 622:A160. [28]Stroud et al. this conference. [29] Nittler et al. this conference. [30] Remusat et al. this conference. [31] Kebukawa et al. thisconference. [32] Bonal et al. this conference.

Soluble Organic Matter (SOM) analysis of the Hayabusa2 samples: The first results
Hiroshi Naraoka1, Yoshinori Takano2, Jason P. Dworkin3, Kenji Hamase1, Aogu Furusho1, Minako Hashiguchi4, Kazuhiko
Fukushima4, Dan Aoki4, Yasuhiro Oba5, Yoshito Chikaraishi5, Saburo Sakai2, Nanako O. Ogawa2, Naohiko Ohkouchi2,
Toshihiro Yoshimura2, Toshiki Koga2, Haruna Sugahara6, Hajime Mita7, Daniel P. Glavin3, Jamie E. Elsila3, Eric T. Parker3,
José C. Aponte3,8, Hannah L. McLain3,8, Heather V. Graham3, John M. Eiler9, Francois-Regis Orthous-Daunay10,
Cédric Wolters10, Véronique Vuitton10, Roland Thissen10, Junko Isa11, Philippe Schmitt-Kopplin12, Norbert Hertkorn12,
Alexander Ruf13, Hisayoshi Yurimoto5, Tomoki Nakamura14, Takaaki Noguchi15, Ryuji Okazaki1, Hikaru Yabuta16,
Kanako Sakamoto6, Shogo Tachibana6,17, Seiichiro Watanabe4 and Yuichi Tsuda6
1

Kyushu Univ.,2JAMSTEC, 3NASA Goddard Space Flight Center, 4Nagoya Univ., 5Hokkaido Univ., 6JAXA, 7Fukuoka Inst.
Tech. 8Catholic Univ/CRESST, 9California Inst. Tech., 10Univ. Grenoble Alpes CNRS IPAG, 11Tokyo Inst. Tech.,
12Helmholtz-Zentrum Muenchen, 13Aix-Marseille Univ., 14Tohoku Univ., 15Kyoto Univ. 16Hiroshima Univ., 17Univ. Tokyo

The Hayabusa2 spacecraft successfully collected the surface and possible sub-surface materials of the asteroid 162173 Ryugu.
Ryugu is a C-type asteroid characterized by a low-albedo surface probably consisting of hydrous minerals and carbonaceous
materials. [1] The direct optical and spectral analysis of the returned samples indicates that Ryugu material is dominated byhydrous carbonaceous chondrite-like matter (similar to CI chondrites) [2]. Since carbonaceous chondrites have generally
yielded various types of organic matter, the collected Ryugu grains are expected to contain diverse types of organic
compounds including bio-related molecules. The occurrence of organic compounds in the Ryugu surface will provide clues tothe evolution of prebiotic molecules and their preservations associated with aqueous alteration of the primitive asteroid. The
initial analysis of soluble organic matter (SOM) of the Hayabusa2-returned samples has been performed by an internationalteam consisting of 32 members. Because the sample amount available for comprehensive SOM analyses is limited, andbecause the SOM is expected to be present as a complex mixture of various types of organic compounds with very small
concentrations of each compound, high-sensitivity and high-resolution analytical techniques have been developed using
carbonaceous meteorites [e.g. 3].
Two aggregate samples of the Ryugu grains (A106 and C107) were allocated for the solvent extractions and total
carbon (C), hydrogen (H), nitrogen (N), sulfur (S) and oxygen (O) measurements. The A106 sample was collected during the
1st sampling in February 2019 and the C107 sample was collected during the 2nd sampling in July 2019 after the Small Carry
Impactor (SCI) operation. They consist mainly of particles smaller than 1 mm in diameter, and each sample mass was 38-39
mg. They were firstly investigated spectroscopically in the near infrared wavelength range by the Stone Team prior to thesolvent extractions. Other small grains (A0080 and C0057) were also allocated for this study to investigate the spatial
distribution of organic compounds on the sample surface. The extraction and analytical measurements implemented by the
SOM Team are summarized in Figure 1. Each powder sample was extracted sequentially with non-polar to polar solvents, i.e.,hexane, dichloromethane (DCM), methanol (MeOH) and H2O, for non-targeted analysis to reveal the compound composition.
Each solvent extract was analyzed by solution state nuclear magnetic resonance (NMR) spectroscopy [4], Fourier transformion cyclotron resonance/mass spectrometry (FT-ICR/MS) with ESI and APPI ionization [5] and by high-resolution mass
spectroscopy using Orbitrap MS coupled with nano-liquid chromatography (nanoLC/Orbitrap MS) [6], and using two
dimensional gas chromatography/mass spectrometry (GC×GC/MS). The extracted residues were passed to the Chemistry
Team for further inorganic element analysis. The other powder sample was subjected to the hot water extraction for amino acidanalyses including chiral isomer separation, which was performed by three-dimensional (3D) high-performance liquid
chromatography (HPLC) with high-sensitivity fluorescence detection (FD) [7] and by HPLC/FD coupled with quadrupole-timeof flight/mass spectrometry (QToF/MS) [8]. After the hot water extraction, the residue was split into two halves. One half was
further extracted with hydrochloric acid (HCl) to analyze for amino acids in bound-form. The other half was sequentiallyextracted with DCM/MeOH (1/1) to analyze semi-polar compounds such as polycyclic aromatic hydrocarbons (PAHs) by
GC/MS, followed by further extraction with formic acid to analyze polar heterocyclic compounds, and subsequent extraction
with HCl to detect bound-form polar compounds. The extracted residues were passed to the IOM Team for the analysis of
insoluble organic matter (IOM). Compound-specific stable isotope analyses will be performed using GC/combustion/isotope
ratio mass spectrometry (GC/C/IRMS) if the compound concentration is high enough to enable such an isotopic measurement.
All extraction procedures were performed on an ISO 6 (Class 100) clean bench inside an ISO 5 (Class 1000) clean room.
Baked serpentine powder was also analyzed as a procedural blank. In situ organic compound analysis with the molecularimaging was performed using desorption electrospray ionization (DESI) equipped with Orbitrap MS [9, 10], followed byspatial imaging of organic compounds using ToF/secondary ion mass spectrometry (ToF/SIMS) [11]. The bulk chemical andisotopic compositions of CNS and HO were determined using nano-elemental analysis/isotope ratio mass spectrometry(nanoEA/IRMS) [12] and EA/pyrolysis/IRMS, respectively.
We have identified a variety of indigenous organic compounds in the extracts of both A106 and C107 samples. The
Ryugu grains host organic molecules under the high-vacuum and cosmic-ray irradiation environment of the asteroid surface.
The analysis of extracted molecules is in progress, and the first results will be presented at the symposium.

Figure 1. Analytical scheme for the Ryugu samples by the SOM Team.

References[1] Kitazato K. et al. (2019) Science 364, 272. [2] Yada T. et al. (2021) Nature Astron. in press. [3] Naraoka H. et al. (2019)
Life 9, 62. [4] Hertkorn N. et al. (2015) Magn. Reson. Chem. 53, 754. [5] Schmitt-Kopplin P. et al. (2010) PNAS USA 107,2763. [6] Naraoka H. et al. (2017) ACS Earth & Space Chem. 1, 540. [7] Furusho A. et al. (2020) J. Chromatogr. A 1625,
461255. [8] Glavin D. P. et al. (2021) MAPS 56, 148. [9] Naraoka H. & Hashiguchi M. (2018) Rapid Commun. Mass Spectrom.
32, 959. [10] Hashiguchi M. & Naraoka H. (2019) MAPS, 54, 452. [11] Naraoka H. et al. (2015) EPS 67, 67. [12] Ogawa N. O.
et al. (2019) 82nd METSOC Meeting, Abstract #6208.

A first look at the interior and exterior of Ryugu preserved in samples collected by Hayabusa2
Eizo Nakamura1, Katsura Kobayashi1, Ryoji Tanaka1, Tak Kunihiro1, Hiroshi Kitagawa1, Christian Potiszil1, Tsutomu Ota1,
Chie Sakaguchi1, Masahiro Yamanaka1, Yusuke Yati1,Tomohiro Usui2, Yuichi Tsuda2, Seichiro Watanabe3, Masanao Abe2,
Tatsuaki Okada2, Toru Yada2
1
The Pheasant Memorial Laboratory, Inst. for Planetary Materials, Okayama Univ. at Misasa, Tottori 682-0193, Japan.
2Inst. Space Astronaut. Sci., Japan Aerosp. Explor. Agency (JAXA), Kanagawa 252-5210, Japan
3
Dept Earth Planet. Sci., Grad. Sch. Sci., Nagoya Univ., Nagoya 464-8601, Japan.
Sample return missions represent great opportunities to study materials from known locations. The Hayabusa mission returnedmaterial to Earth from the asteroid Itokawa in 2010 and revealed through geochemistry and micro-petrograpy that it isgenetically related to ordinary chondrite meteorites and the surface of the modern-day asteroid is being actively bombarded byhyper-velocity small particles (e.g., Kawaguchi et al., 2003; Nakamura et al., 2012). The Hayabusa2 mission returned material
to Earth from Ryugu on 6th of December, 2020 (Tsuda et al., 2020). Based on the very low geometric albedo indicated byremote observations (Sugita et al., 2019; Kitazato et al., 2019), abundant organic matter on Ryugu, compared to those incarbonaceous chondrites, might be expected (Potiszil et al., 2020). The initial uncontaminated and non-destructive
observations for the entire set of returned samples in the Phase-1 Curation at JAXA/ISAS (Yada et al., 2021) demonstrated
that Hayabusa2 retrieved the representative and unprocessed (albeit slightly fragmented) Ryugu sample. The data further
expanded on the indications from the remote sensing observations that Ryugu is dominated by hydrous carbonaceouschondrite-like materials, similar to CI chondrites, but with an optically darker, more porous, and more fragile nature.
In order to analyze both organic and inorganic matter, the pieces of Ryugu were subject to in-depth investigations in the
Pheasant Memorial Laboratory (PML), Okayama University at Misasa. The 16 particles of Ryugu sample (A0022, A0033,
A0035, A0048, A0073, A0078, and A0085 from the natural surface of the equatorial region of Ryugu, and C0008, C0019,
C0027, C0039, C0047, C0053, C0079, C0081, and C0082 from the surrounding site of the artificial impact crater on Ryugu;
total ~55 mg) were selected during the Phase-1 Curation. The selected samples were then transferred to the ultimate clean
room in the PML for Phase-2 Curation, to catalog the samples via a comprehensive analytical strategy.
The particles were first characterized under digital optical microscope and then their volume and mass were measured
to determine their densities. The average density was 1530 ± 250 kg m-3, which was systematically larger than the value
reported in Yada et al (2021). To elucidate the systematic differences among the 16 pieces, both plainer surfaces and powder
were created from each piece using an ultra-microtome equipped with a diamond knife. The surface was observed using
optical microscope and SEM, the major element distribution and mineral phases were determined by EDS installed in SEM,
micro-Raman spectroscopy, micro-XRD and TEM, all without coating. Subsequently, major and trace element compositions
were determined from a given powder by ICP-MS. Element and isotope compositions of H, C, N and O were determined bygas-source mass-spectrometry, and those of Ne were determined by laser-heating noble-gas-mass-spectrometry using small
broken pieces. Solvent soluble organic matter was extracted from sample powders using various solvents, including water,acetonitrile, ethyl acetate and formic acid. Meanwhile, insoluble organic matter was isolated after solvent extraction anddemineralization by HCl, HF and boric acid. After the first-round characterization, the microtomed surfaces were surveyedusing micro-Raman spectroscopy, SIMS and desorption electrospray ionization-orbitrap-mass spectrometry (DESI-OT-MS).
The 16 pieces were found to consist of magnetite, carbonate, phosphates, sulfides and minor silicate fragmentsinterfiled by matrix (modal abundance of 86-96%) that was dominated by sub-micron-sized phyllosilicates. Average modal
abundances of the aforementioned phases (excluding matrix) were 3.7, 2.4, 0.8, 2.5 and 0.4 %, respectively. The
phyllosilicates were mainly composed of the serpentine and smectite groups. As noted by the Phase-1 Curation, the existenceof high-temperature nebular products, such as refractory inclusions and chondrules were not found. The magnetite was present
as micron-sized euhedral to subhedral grains and sub-micron-sized grains with a framboidal and plaquette texture. Noncarbonate carbon-rich phases of several micrometers in size, were discovered embedded in the matrix (modal abundance is~0.2%). The presence of soluble and insoluble organic matter was confirmed by DESI-OT-MS and FTIR and micro-Raman
spectroscopy, respectively. Further characterization of the solvent soluble fraction via HPLC-OT-MS and GC-MS is currently
underway. The organic matter is ubiquitous in the matrix according to observations by SIMS and micro-Raman spectroscopy.

The major and trace element compositions and O isotope composition are homogenous, with the major and traceelement compositions representing the proto-solar abundance of Lodders (2020). However, a significant variation of H, C, N
and Ne isotopic compositions at the sub-mm scale among the particles was found, which suggests that Ryugu has experienced
a complex evolutionary history.
In this talk, preliminary results from the Misasa Phase2 Curation team will be presented.
References
Kawaguchi, J. et al., The MUSES-C mission for the sample and return—its technology development status and readiness, Acta
Astronautica, 52, 117-123, 2003.
Kitazato, K., et al., The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy, Science
364, 272-275, 2019.
Lodders, K., Relative Atomic Solar System Abundances, Mass Fractions, and Atomic Masses of the Elements and Their
Isotopes, Composition of the Solar Photosphere, and Compositions of the Major Chondritic Meteorite Groups. Space
Science Reviews, 217, 1-33, 2021.
Nakamura, E. et al., Space environment of an asteroid preserved on micrograins returned by the Hayabusa spacecraft,
Proceedings of the National Academy of Sciences of the United States of America, 109, E624-E629, 2012.
Potiszil, K. et al., The Albedo of Ryugu: Evidence for a High Organic Abundance, as Inferred from the Hayabusa2
Touchdown Maneuver, Astrobiology, 20, 916-921, 2020.
Sugita, S. et al., The geomorphology, color, and thermal propertiesof Ryugu: implications for parent-body processes, Science
364, eaaw0422, 2019.
Tsuda, Y. et al., Hayabusa2 mission status: landing, roving and cratering on asteroid Ryugu, Acta Astronautica 171, 2-54,
2020.
Yada, T. et al., Ryugu: A brand-new planetary sample returned from a C-type asteroid, Nature Astronomy, in press, 2021.

The C-type asteroid Ryugu:
A first detailed look by Phase2 Curation Kochi (Ph2K)
M. Ito1, N. Tomioka1, M. Uesugi2, A. Yamaguchi3, N. Imae3, N. Shirai4, T. Ohigashi5, M. Kimura3, M-C. Liu6,
R.C Greenwood7, K. Uesugi2, A. Nakato8, K. Yogata8, H. Yuzawa5, Y. Kodama9*, M. Yasutake2, R. Findlay7, I.A Franchi7,
J.A. Malley7, K. Hirahara10, A. Tsuchiyama11, A. Takeuchi2, I. Sakurai12, I. Okada12, Y. Karouji13, T. Yada8, M. Abe8,
T. Usui8, S. Watanabe12, and Y. Tsuda8.
1
8

JAMSTEC Kochi, 2JASRI/SPring-8, 3NIPR, 4Tokyo Met. Univ., 5UVSOR/IMS, 6UCLA, 7Open Univ.,
JAXA/ISAS, 9MWJ, 10Osaka Univ., 11Ritsumeikan Univ., 12Nagoya Univ., 13JAXA/JSEC, *Toyo Corp.

The Hayabusa2 spacecraft successfully returned to
Figure 1. Largest Ryugu sample (A0002) for the Phase 2 curation
Earth surface materials from the C-type asteroid 162173
Kochi. (a) optical and (b) 3D-reconstruct images
Ryugu on December 6th 2020. The sample capsule contained(a)(b)
a large number of small grains (a few to several mm in size),
collected from touchdown sites 1 and 2 on Ryugu, with a total
mass of ~5.4 g [1, 2]. After initial characterization of thegrains by JAXA curation (e.g., size, weight, FTIR andMicrOMEGA spectroscopic survey), we received eight grains(four from Room A and four from Room C) on June 17, 2021
(Figure 1 and Table 1). Detailed study of the materials
returned from Ryugu will provide critical information about the origin and early evolution of the Solar System and in particular,
the nature of the asteroid-meteorite connection, water-rock interactions on asteroids, the evolution of organics on small bodies,
the diversity and history of asteroid families in the main belt.
On June 19, 2021, we started initial characterization studies of all our samples using synchrotron radiation-based CT
and XRD at the SPring-8. An air-tight sealed carbon nano-tube sample holder was used for CT analysis. In order to avoid
degradation and contamination due to interaction with the terrestrial atmosphere (water vapor and oxygen gas) [3], all of thesample preparation (chipping by a chisel, cutting by a counter balanced diamond wire saw, and epoxy mount preparation) was
conducted in a glove box in an atmosphere of pure, dry N2 (Dew point: -80 to -60˚C, O2 ~50 to 100 ppm). Once we had acquired
high-resolution, detailed three-dimensional structural and crystallographic information (0.85 µm/pixel for CT) for each of oursamples, we were able to define a priority list for the next phase of the analytical campaign, which involved coordinated micro
and bulk analysis.
The micro-analysis plan proposed by Ph2K involves the use of a wide range of multi-beam instruments to acquiredetailed micro-textural and chemical information about the samples at a sub-micrometer scale. Ongoing studies have involved
the use of FIB, STXM-NEXAFS, NanoSIMS and TEM [4]. In parallel, we are conducting bulk analysis of the samples using
SEM-EDS, EPMA, Raman spectroscopy, XRD, large geometry type SIMS, high precision O isotopic analysis by laser
fluorination and INAA. We have used air-tight containers (a facility-to-facility transfer container, FFTC [4]) for sample
transportation to nation-wide institutes by hand carry. With the assistance UK embassy in Tokyo, a few representative grains
were delivered to the Open University without any potentially invasive inspection (i.e., X-ray).
In this talk, we will present the preliminary results of the Ph2K coordinated micro-analysis and systematic bulk chemical
analysis campaign, which is focused on providing a detailed understanding of these precious Ryugu returned samples.
References: [1] Morota T. et al. 2020. Science 368, 654–659. [2] Yada et al. 2021. Abstract#2008, 52nd LPSC. [3] Uesugi M.
et al. 2020. Rev. Sci. Instrum. 91, 035107. [4] Ito M. et al., 2020. Earth, Planets and Space 72, 133.
Table 1. The Ryugu samples for the Phase2 curation Kochi
Sample No.

mgµm

SPring-8

Microanalysis(STXM, NanoSIMS, TEM)

Bulk Analysis(SEM-EDS, EPMA, Raman)

A0002

19.3

4,092

HR-CT, XRD, XRD-CT

Y

A0029

9.1

3,069

HR-CT, XRD, XRD-CT

Y

Y

A0037

7.8

3,129

HR-CT, XRD, Phase-contrast CT

Y

Y

A0098

1.9

1,868

HR-CT

C0009

11.1

3,520

HR-CT, XRD, XRD-CT

C0014

6.8

3,527

HR-CT

C0068

1.68

1,980

HR-CT

C0087

2

3.242

HR-CT

High Precision
O isotopes

SIMS

Y

XRD

Y
Y
Y

Y

INAA

Y

Y

Y

Y

Y

Y
Y

Y

Y

Y

Y
Y

Y
Y

JAXA Detailed Description -Variation of surface characteristics of Ryugu returned samplesAiko Nakato1, Toru Yada1, Kasumi Yogata1, Akiko Miyazaki1, Kentaro Hatakeda1,2, Kazuya Kumagai1,2, Masahiro
Nishimura1, Yuya Hitomi1,2, Hiromichi Soejima1,2, Kana Nagashima1, Jean-Pierre Bibring3, Cedric Pilorget3, Vincent Hamm3,
Rosario Brunetto3, Lucie Riu3, Lionel Lourit3, Damien Loizeau3, Tania Le Pivert-Jolivet3, Guillaume Lequertier3, Aurelie
Moussi-Soffys4, Masanao Abe1, Tatsuaki Okada1 and Tomohiro Usui1
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2Marine Works Japan, Ltd., 3Institutd'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 4Centre National d'Etudes Spatiales
The Ryugu sample brought back by the Hayabusa2 spacecraft in December 2020 weighed ~5.4 g, which is much larger
than we expected [1, 2]. After the samples were delivered to JAXA Extraterrestrial Curation Center, individual grains have been
picked up and stored into sapphire dish, and analyzed by optical microscope, weighting, FTIR spectroscopy, and MicrOmega
hyperspectral imaging [3] for initial description [2]. The obtained data will open in early 2022 for International Announcementof Opportunity (AO) through curatorial Database System for Ryugu Sample [4]. During the ffirst 6 months, we observed 205
individual grains, 100 from chamber A and 105 from chamber C. There are some unique characteristic features on the surface.
Here, we propose a morphological classification of these surface features into 4 groups, based on visible characteristics of Ryugu
samples. 1/ Dark and fluffy: these features are dominant in Ryugu samples; 2/ Dark and glossy: they are present either on a partor on the entire of grain; 3/ Bright: also present either on a part or on the entire of grain; 4/ White regions: they are observed over
300 μm in size. Those characteristics may be observed alone or in duplicate on a single grain.
In July 2021, 4 grains showing those different features, were allocated as JAXA detailed description (JAXA-DD) (Fig.1). We
conduct petrological and mineralogical observation by SEM and XRD to understand the linkage with surface characteristics
obtained by the initial description. The purpose of this study is to contribute to the sample selection by researchers at Int’l AO.
FE-SEM/EDS observation was performed using Hitachi SU6600 equipped with slow purge system in order to non-airexposure transportation from glove box to SEM, on the front surface where the main initial description was made. For two
grains A0017 and C0094, where the entire front surface shows unique characteristics, SEM observation was also performed on
the back surface. After these observations, we performed a sample chipping under pure N2 atmosphere inside Glove Box. A
specially developed tantalum chisel is used for the division. Since tantalum is also used as a bullet when collecting samples on
the asteroid, it was selected as materials for the purpose of unifying the potential sources of sample contamination. From thedivided sample, we separated small portions showing each of the four characteristics and we performed additional SEM
observations. We handled the samples under non-air-exposure environment until the sample division. The small portions areattached to carbon fiber with glue for future XRD analysis using RIGAKU RA-Micro7 HFMR.
In this presentation, we will introduce the variations of Ryugu sample surface characteristics, reflecting variations of theirmineralogy and petrography, coordinated with JAXA initial description.

A0042

C0094

A0017

C0041

Figure 1. Optical microscopic images of 4 grains allocated to JAXA-DD.
a) A0042：Dark and fluffy feature is dominant in Ryugu samples. b) C0094: Dark and glossy characteristic is appeared on entire surface.
c) A0017: Bright area cover most of the front surface. d) C0041: White region is shown at the right bottom and left top of grain.

References: [1] Tachibana S. et al. (2021) LPS, XXXXXII, Abstract #1289. [2] Yada T. et al. (2021) LPS, XXXXXII,
Abstract #2008. [3] Bibring J.-P. et al (2017) Space Sci. Rev. 208, 401-412. [4] Nishimura M. et al. (2021), Astromaterials
Data Management in the Era of Sample-Return Missions Community Workshop, Abstract.

Overview of the features of returned samples from the C-type asteroid 162173 Ryugu
based on optical microscope observations and their weights
A. Miyazaki1, T. Yada1, M. Abe1,2, A. Nakato1, K. Yogata1, K. Nagashima1,
K Hatakeda1,4, K. Kumagai1,4, M. Nishimura1, Y. Hitomi1,4, H. Soejima1,4, M. Yoshitake1, A. Iwamae1,4,S. Furuya1,3, K. Sakamoto1, T. Okada1,3, S. Tachibana1,3, H. Yurimoto1,5, T. Usui1
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency,
2
The Graduate University for Advanced Studies (SOKENDAI) ,3University of Tokyo,
4
Marine Works Japan, Ltd.,5Hokkaido University.
Hayabusa2 collected the surface and sub-surface material from the C-type near-Earth asteroid 162173 Ryugu and brought back
5.4 g of samples in total to the Earth [1]. The samples were collected during the two touch-down operations: the samples collected
for the first touch-down (TD1) were stored in the Chamber A of the sample catcher, and those collected for the second touchdown (TD2), which was done near the artificial crater made by the SCI [2], were stored in the Chamber C [3]. In the cleanchamber dedicated to Hayabusa2 samples [4], the samples in the Chambers A and C were first put in individual sapphire
containers for the initial characterization of bulk properties. The samples were first observed with an optical microscope and it
was found that the samples from both chambers were aggregation of black-colored mm-sized pebbles and sub-mm sized fine
powder, with millimeter-scale particles being the most common [5]. A few centimeter-sized pebbles were also found in thesamples recovered from the Chamber C [1]. Then, weight analysis, optical spectroscopy and visual multispectral imaging were
performed for the initial characterization. We will present here the features of the individual returned samples based on the
microscopic observations and weight analyses.
Pebbles of 1–10 mm in size were removed from the sapphire containers to individual small sapphire dishes. For the first six
months after the sample receipt, 100 pebbles from the Chamber A and 105 from the Chamber C were hand-picked one-by-one
with vacuum tweezers in the clean chamber under ultra-purified nitrogen atmosphere without exposing to terrestrial atmosphere[6]. The samples in the sapphire dishes are first photographed with an optical stereomicroscope equipped above the cleanchamber through a glass window. The size of the individual samples is measured from the microscopic images. Then, the grossweight of the sample and the sapphire dish in the stainless steel capsule was measured with a microbalance equipped in the CC.
The weight of an individual sample inside the dish is calculated based on the gross weight of the dish in the stainless steel capsule
which was measured in advance.
The preliminary results were reported in [3] and [5]. The observed Ryugu samples have dark spectral features. Many bright andpatchy fine inclusions are observed on the surface of some pebbles, but no apparent high temperature components like chondrules
nor Calcium-Aluminum-rich-Inclusions (CAI) has been observed with optical microscope analyses [5]. These pebbles show
significant morphological variations; grains with rugged surface and with smooth surfaces are observed [3]. These two types offeatures were also found on the surface textures on Ryugu boulders [7]. Many pebbles are also found to feature curved andstraight cracks and some pebbles show elongated block-like morphologies [3]. Densities of individual grains are estimated fromthe grain weight and the volume of approximated spheroid evaluated from the optical observation, leading to the average densityof 1282 ± 231 kg m-3. This density is much lower than the typical grain density of CI chondrites [5]. We will present moredetailed features of the returned individual samples.
References[1] Yada T et al., 2021. 52nd LPSC, abstract#2008. [2] Arakawa M. et al. 2020, Science 368:67. [3] Tachibana S. et al. Submitted
to Science. [4] Abe M. et al., 2021. This meeting. [5] Yada T. et al. Submitted to Nature Astronomy. [6] Yada T. et al., 2014.
Meteoritics Planet. Sci. 49:135. [7] Cho Y. et al., Submitted to Planet. Space Sci.

Initial description of Ryugu returned samples: characteristics of individual grains by FT-IR
analysis
Kentaro Hatakeda1,4, Toru Yada1, Masanao Abe1,2, Tatsuaki Okada1,3, Aiko Nakato1, Kasumi Yogata1, Akiko Miyazaki1,
Kazuya Kumagai1,4, Masahiro Nishimura1, Yuya Hitomi1,4, Hiromichi Soejima1,4, Kana Nagashima1, Miwa Yoshitake1, Ayako
Iwamae1,4, Shizuho Furuya1,3, Tomohiro Usui1, Shogo Tachibana1,3, Kanako Sakamoto1, Kohei Kitazato5, Hisayoshi Yurimoto6
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan,
2
The Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan
3
University of Tokyo, Bunkyo, Tokyo 113-0033, Japan,
4
Marine Works Japan, Ltd., Yokosuka 237-0063, Japan,
5
The University of Aizu, Aizu-Wakamatsu 965-8580, Japan,
6
Hokkaido University, Sapporo 060-0810, Japan.
A total of ~5.4 g of sample was collected at the surface of the C-type asteroid 162173 Ryugu and successfully returned to
Earth [1] [2]. The collected samples were transported to the curation facility in ISAS, Sagamihara, Japan, and stored in purified
nitrogen condition, except for a few grains picked up under vacuum condition, to keep the samples as physically and chemicallypristine as possible. Approximately 100 grains have been picked up from each of those in Chamber A, uppermost centimeterscale layer of Ryugu collected during the first touch-down sampling (TD1), and in Chamber C, surface to subsurface layer (~1m) of Ryugu collected close to the artificial crater during the second touch-down sampling (TD2). Then, initial descriptions,such as weighing, optical imaging, FT-IR spectroscopy in 1-5 µm range, MicrOmega as a hyperspectral NIR microscope, andvisual multispectral imaging, have been performed for characterization of these samples. Here we present the preliminary resultof FT-IR spectral analysis for individual grains.
The measurement system consists of the spectrometric unit outside the clean chamber and the sample chamber connectedto the clean chamber (Figure 1). Although purified nitrogen gas flowed inside the spectrometric unit, absorption bands of O-H(e.g., H2O) and that of C-O (CO2) appeared in the reflectance spectra of reference material (Infragold) measured after the sample
analysis, indicating the influence of spectral absorption in the atmosphere. In addition, the spot size of the incident beam, approx.
1 mm in diameter at the focal position, was slightly larger than the sizes of individual grains in many cases, and these data were
contaminated by the reflectance from the sapphire dish at the bottom of the sample holder. The reflection from the sapphire dishincreased the albedo, changed the spectral slope between 1 and 2.5 µm from positive to negative, and decreased the absorption
band depth (Figure 2).
Except for the samples with significant effect of sapphire dish, reflectance spectra of individual grains generally show asimilar trend to those of bulk samples [3] in the wavelength range between 2.5 and 4 µm. The depth of absorption bands varied
between grains, and the band-depth variation is observed not only between the individual grains but also within the single grain.
We also found grains with unique spectral profiles, of which abundance is ~1% or less. These grains basically contain relatively
large inclusions, which are apparently different from the surrounding matrix.
We are now planning to modify the FT-IR system to extend to the mid to far-infrared wavelength range, and expect to getfurther information on the collected Ryugu samples.

Figure 1. Overview of the FT-IR measurement system

Figure 2. The mixing effect of the sapphire dish reflectance. The larger effect was observed with increasing the area where incident
beam illuminated the sapphire dish; A) Reflectance spectra (%), B) Normalized reflectance at 2.6 µm, C) Normalized reflectancewith continuum at 2.6-3.2 µm and NIRS3 spectral data [4], D) Normalized reflectance with continuum at 3.3-3.6 µm.

References[1] Tachibana S. et al. (2021) LPS, XXXXXII, Abstract #1289. [2] Yada T. et al. (2021) LPS, XXXXXII, Abstract #2008.
[3] Yada T. et al. in press. Nature Astronomy. [4] Kitazato et al. (2019) Science 364: 272.

MicrOmega detections of C-rich phases in Ryugu returned samples within the Hayabusa2 JAXA
Extraterrestrial Curation Center
Bibring1, J.-P.; Brunetto1, R.; Carter1, J,; Gondet1, B.; Pilorget1, C.; Hamm1, V.; Hatakeda2, K; Langevin1, Y.; Lantz1, C., Le
Pivert-Jolivet1, T.; Loizeau1, D.; Nakato2, A.; Okada2, T.; Riu1,2, L.; Usui2, T.; Yada2, T.; Yogata2, K., 1Institutd'Astrophysique Spatiale, Université Paris-Saclay, CNRS, 2Institute of Space and Astronautical Science, Japan Aerospace
Exploration Agency
The Ryugu samples brought back by the Hayabusa2 spacecraft in December 2020 have been delivered to the JAXA
Extraterrestrial Curation Center [1, 2]. Bulk samples and then individual grains have been deposited onto sapphire dishes,
weighted, and analyzed with optical microscopy, FTIR spectroscopy, and MicrOmega hyperspectral imaging [3] for initialdescription [2]. The MicrOmega instrument used in the JAXA Extraterrestrial Curation Center is a NIR hyperspectral
microscope. It images samples ~ 5 mm x 5 mm large, with 250x256 pixels of ~22 µm in size. Its spectral capability covers therange from 0.98 µm to ~3.6 µm, which gives access to primary and secondary minerals and organic matter, in particular throughtheir OH, CO3, and CH features [4, 5].
As presented in the Yada et al. and Pilorget et al. talks (this conference), the averaged spectra of Ryugu returned samples present
two major features, centered around 2.7 and 3.4 µm, attributed to OH-rich and CH-rich compounds respectively. Thanks to the
MicrOmega capability to characterize the spectral signatures of returned grains down to the few tens of µm scale, a variety of
C-rich compositions do show up, through the following features:- variability in the central position and shape of the 3.4 µm dominant absorption, with a minimum varying from 3.35 µm to 3.45
µm, and the occasional presence of several local minima with varying spectral band areas. These observations suggest organic
matter of varying composition and structure is present over the entire samples;- the presence of coupled spectral features such as at around 2.85 µm, 3.1 µm or 3.55 µm, with their associated band ratios.
Additional spectral structures < 2.7 µm are in some cases observed and correlate with them. These bands collectively suggest
organic carbon is at times bound to non-C groups or intimately mixed with specific minerals.
- the ratio between the 2.7 µm and 3.4 µm band depths spans a very wide range of values, with some grains highly depleted ineither OH-rich or CH-rich phases.
These spectral features are diagnostic of specific C-rich compositions and of their spatial heterogeneity in the collected samples
at the scale of few tens to few hundred microns. We shall present a preliminary review of the observed diversity, and discuss itin terms of the composition and origin of the potential carriers.

References[1] Tachibana S. et al. (2021) LPS, XXXXXII, Abstract #1289. [2] Yada T. et al. (2021) LPS, XXXXXII, Abstract #2008. [3]Bibring J.-P. et al (2017) Space Sci. Rev. 208, 401-412. [4] Pilorget C. and Bibring J.-P. (2014) PSS 99, 7-18. [5] Pilorget C. et
al. (2021) this conference.

MicrOmega detections of carbonates in Ryugu returned samples within the Hayabusa 2 JAXA
Extraterrestrial Curation Center
Loizeau, D.1; Bibring, J.-P.1; Brunetto, R.1; Pilorget, C.1; Okada, T.2,3; Carter, J.1;Gondet, B.1; Hamm, V.1; Hatakeda, K.2,4;
Langevin, Y.1; Lantz, C.1; Le Pivert-Jolivet, T.1; Nakato, A.2; Riu, L.2; Usui, T.2,3; Yada, T.2; and Yogata, K.2;
1
Institut d'Astrophysique Spatiale, Université Paris-Saclay, CNRS, France
2
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan 3University of Tokyo,
Bunkyo, Japan, 4Marine Works Japan, Ltd., JapanThe Ryugu samples brought back by the Hayabusa2 spacecraft in December 2020 have been delivered to the JAXA
Extraterrestrial Curation Center [1, 2]. Bulk samples and then individual grains have been picked up and stored into sapphire
dishes, weighted, and analyzed with an optical microscope, FTIR spectroscopy, and MicrOmega hyperspectral imaging [3] for
initial description [2]. The MicrOmega instrument used in the JAXA Extraterrestrial Curation Center is a NIR hyperspectral
microscope. It has a total field of view of 5 mm x 5 mm, with resolution of ~22 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 of different minerals
in the returned samples [4]. Initial analyses with MicrOmega were first made on the bulk samples from chambers A and C of
the Hayabusa 2 returned capsule, and then on individual grains stored in their sapphire dishes. 137 out of the 205 extracted
grains have been analyzed with MicrOmega as of September 30, 2021 [5].
In the spectral domain of MicrOmega, carbonates have a strong characteristic double absorption band in the 3.3-3.5 µm area,accompanied by two other weaker bands around 2.5 and 2.3 µm. The exact spectral position of these bands varies with thecation content of the carbonate [6]. Iron-bearing carbonates also show a strong absorption below 1.5 µm.
First detections of carbonates were made in grains included in the bulk samples from both chambers A and C. Some small
grains seem to be entirely carbonate-rich and are up to ~450 µm, down to <50 µm in size. Carbonate inclusions were also
detected in larger grains, with sizes up to ~380 µm in a >1.5 mm-sized grain, and down to <50 µm (figure 1-A).
From the first 130 analyzed extracted grains, MicrOmega detected carbonate inclusions with high confidence in 19 of thosegrains. The largest detection was made on grain C0041, covering ~0.25 mm , or ~10% of the visible surface of the grain(figure 1-B). This grain is one of the grains with “White regions” as described in Nakato et al. [7].
In terms of spectral characteristics, they all present a double band at 3.31-3.47 µm and a band centered at 2.71 µm. The largest
grains and inclusions also exhibit spectral bands at 2.51 and 2.30 µm, also characteristic of carbonates, and a deep absorption
below 1.5 µm. Some detections also have a band at 2.77 µm (present in many carbonate reference spectra), and some between
3.07 and 3.10 µm. The presence of a strong absorption below 1.5 µm indicates the likely presence of Fe2+ in the carbonate
mineral, although the position of the bands around 2.3, 2.5 and 3.4 µm is shifted to shorter wavelength compared to a purely
Fe2+ carbonate (siderite), and would better fit Mg-bearing carbonates like dolomite or magnesite. The iron-bearing magnesite
breunnerite is a likely candidate for these detections. Smaller grains and inclusions do not show the absorption below 1.5 µm,
while the other absorptions are centered around the same positions than for the larger grains (figure 1-C). Likely candidates
include dolomite and magnesite.
Such carbonate grains and inclusions within the returned samples from Ryugu are a key to understand the evolution of theasteroid. MicrOmega can help mapping and quantifying the presence of these carbonates throughout the collection.

Figure 1. Example of carbonate detections with MicrOmega on bulks from chamber A and C, and on an extracted grain from chamber C.
Left: MicrOmega images with red pixels where carbonate is detected. A: extracted grain C0041. B: bulk samples from chamber A. C: bulk
samples from chamber C. Right: Average spectra of pixels with carbonate detections within the colored boxes in the left images.

References[1] Tachibana S. et al. (2021) LPS, XXXXXII, Abstract #1289. [2] Yada T. et al. (2021) LPS, XXXXXII, Abstract #2008. [3]Bibring J.-P. et al (2017) Space Sci. Rev. 208, 401-412. [4] Pilorget C. and Bibring J.-P. (2014) PSS 99, 7-18. [5] Pilorget C. et
al. (2021) this conference. [6] Hunt G.R. and Salisbury J.W. (1971) Visible and near infrared spectra of minerals and rocks. II.
Carbonates. Modern Geology 2, 23–30. [7] Nakato A. et al. (2021) this conference.

The 2.7µm OH band in different grains of Ryugu from the two collection sites, as seen by
MicrOmega in the Hayabusa2 Curation Facility
Tania Le Pivert-Jolivet1, Jean-Pierre Bibring1, Rosario Brunetto1, Cedric Pilorget1, Tatsuaki Okada2, John Carter1, Brigitte
Gondet1, Vincent Hamm1, Kentaro Hatakeda2,3, Yves Langevin1, Cateline Lantz1, Damien Loizeau1, Aiko Nakato2, Lucie
Riu1,2, Tomohiro Usui2, Toru Yada2 and Kasumi Yogata2
1

IAS, Université Paris-Saclay, CNRS, France, 2Institute of Space and Astronautical Science, Japan Aerospace Exploration
Agency, 3Marine Works Japan, Ltd

Hayabusa2 is the first space mission to study and collect samples from a C-type asteroid. In December 2020, thespacecraft brought back to Earth ~5.4g of materials from the surface of asteroid (162173) Ryugu. The samples were collectedfrom two different sites TD1 and TD2 [1] at the surface of the asteroid, possibly sampling surface and subsurface materials. The
samples were delivered to JAXA (Japan Aerospace eXploration Agency) Extraterrestrial Curation Center for preliminary
analyses. Individual grains were extracted and analyzed in a controlled N2 environment by an optical microscope, a FTIR
microscope and MicrOmega, a near-infrared (0.99-3.65 µm) hyperspectral microscope. MicrOmega acquires images of 256x250
pixels with a spatial resolution of 22.5 µm. The total field of view covers ~5x5mm [2].
In addition to the bulk samples, observations of individual grains, extracted from the bulks, were performed with
MicrOmega at different azimuth angles to optimize the coverage and avoid potential photometric biases. In order to extract
average spectra of the individual grains (typical size 1-4.5 mm), we developed a novel procedure using thermal emission maps
measured by MicrOmega: first the grains were isolated from the rest of the field of view (the sample holder) thanks to theirdifference in terms of thermal emission, then their pixels were averaged at each azimuth orientation. Spectral parameters were
finally calculated to characterize the position and the depth of the 2.7 µm OH feature. This band is believed to be related to thepresence of metal-OH stretching modes in phyllosilicates [3], and it is observed at large scale over the surface of Ryugu [4].
We shall present the distribution of the spectral parameters of the 2.7 µm feature observed by MicrOmega on grains
extracted from chamber A and chamber C, corresponding to TD1 and TD2 respectively. We will discuss the potential variationsof the spectral parameters, in particular with regards to the observations performed at a much larger scale by NIRS3, and their
possible implications regarding the hydrothermal and space weathering history of the asteroid.
References[1] Tachibana et al. (2020) LPS XXXXXI Abstract #2027. [2] Bibring et al. (2017) Space Sci. Rev. 208, 401-412. [3]Madejová et al. (2017) Developments in Clay Science, 8, 107-149. [4] Kitazato et al. (2019) Science, 364, 272-275

Microscale Diversity of H, C, and N Isotopes in Asteroid Ryugu
Larry R. Nittler1, Jens Barosch1, Bradley T. De Gregorio2, Rhonda M. Stroud2, Hikaru Yabuta3, and The Hayabusa2initial-analysis IOM team, Hisayoshi Yurimoto4, Tomoki Nakamura5, Takaaki Noguchi6, Ryuji Okazaki7, Hiroshi
Naraoka7, Kanako Sakamoto8, Shogo Tachibana8,9, Sei-ichiro Watanabe10 and Yuichi Tsuda8
1Carnegie Institution of Washington, Washington DC, USA, 2US Naval Research Laboratory, Washington DC, USA,
3
Hiroshima Univ., 4Hokkaido Univ., 5Tohoku Univ., 6Kyoto Univ., 7Kyushu Univ., 8JAXA, 9Univ. of Tokyo, 10Nagoya
Univ.
Understanding the nature and origin of organic matter in asteroid 162173 Ryugu is one of the key science goalsof the Hayabusa2 sample-return mission. Macromolecular organic matter (MOM) makes up to a few % of primitive
meteorites and displays a wide range of H, C, and N isotopic ratios on whole-rock to sub-µm scales [1]. Both its origin(for example, whether in the protosolar molecular cloud or in the protoplanetary disk) and the degree to which it ismodified on asteroidal parent bodies is debated, but it may represent the dominant form of C delivered to early Earth.
NanoSIMS-based isotopic imaging surveys of both bulk CI, CR, CM, and CO chondrites and purified MOM residues
from them [2-6] have revealed that, while bulk samples are typically modestly enriched in D and 15N, relative to the
Earth, a small fraction of the material shows much more extreme enrichments and/or depletions in these isotopes.
Large 13C enrichments and depletions are also seen in chondrites, both in presolar circumstellar SiC and graphite
grains [7], and in rare cases in MOM particles [8].
We have begun conducting similar NanoSIMS surveys of Ryugu samples. Four grains from Chamber A
aggregates (A0108) were embedded in S and sectioned with an ultramicrotome equipped with a diamond knife.
Relatively thick (250-nm) slices were deposited onto Si wafers for NanoSIMS analysis while adjacent thin sections
were kept for coordinated analysis by transmission electron microscopy (TEM) and synchrotron X-ray microscopy(STXM). After the S was sublimated, we applied a thin Au coat to the Si wafers and analyzed them with a NanoSIMS
50L ion microprobe in multicollection imaging mode. Microtome sections were first analyzed for C and N isotopes(as 12C2, 12C13C, 12C14N, and 12C15N, plus 16O, 28Si, MgO and secondary electrons) with a 0.4 pA, <200-nm Cs+ beam.
The sections were then re-analyzed at the same magnification with a 1-pA beam and collection of 1H, D, and 12C
secondary ions and secondary electrons. Five of the sections were subsequently re-measured for C and N to improvethe counting statistics. Total counting times varied but were typically of order ~0.1 s/0.01 µm2 for each run.
The measurements reveal broadly similar results to similar data obtained on primitive carbonaceous chondrites.
The four particles show modest bulk enrichments of D and 15N, with D/H and 15N/14N ratios in general agreement withthose of CI chondrites. The NanoSIMS images show that much of the C is present as particles typically a few hundred
nm in size, but ranging up to 2 µm. As in chondrites, a fraction of these particles show more extreme enrichments ordepletions (“hotspots” and “coldspots”) which span ranges similar to those recently seen in the least-altered CM
chondrites Asuka 12169, Asuka 12236, and Paris [3]. A much smaller fraction of C-rich grains shows 13C anomalies,
associated both with presolar grains and organic particles. The bulk and microscale isotopic distributions vary to someextent among the four Ryugu grains, indicating heterogeneity at the 100-µm scale. Planned TEM and STXM
measurements of slices from the same grains will help unravel the chemical nature of the organic particles and theirrelationship to inorganic phases in the asteroid.
References[1] Alexander C. M. O’D. et al. 2017. Chemie der Erde - Geochemistry 77:227. [2] Busemann H. et al. 2006.
Science 312:727. [3] Nittler L. R. et al. 2021. Abstract #6063. 84th Meteoritical Society Meeting. [4] Remusat L. et
al. 2010. The Astrophysical Journal 713:1048. [5] Nittler L. R. et al. 2019. Nature Astronomy 3:659. [6] Nittler L.
R. et al. 2018. Geochimica et Cosmochimica Acta 226:107. [7] Zinner E., 1.4 - Presolar grains, in: A.M. Davis(Ed.), Meteorites and Cosmochemical Processes (Vol. 1), Treatise on Geochemistry (Second Edition, eds: H. D.

Holland and K. K. Turekian), Elsevier-Pergamon, Oxford, 2014, pp. 181–213. [8] Floss C. et al. 2009. AstrophysicalJournal 697:1242.

Diversity of Insoluble Organic Matter at the Nanoscale in Asteroid Ryugu
Rhonda M. Stroud1, Bradley T. De Gregorio1, Larry R. Nittler2, Jens Barosch2, Hikaru Yabuta3, and The Hayabusa2initial-analysis IOM team, Hisayoshi Yurimoto4, Tomoki Nakamura5, Takaaki Noguchi6, Ryuji Okazaki7, Hiroshi
Naraoka7, Kanako Sakamoto8, Shogo Tachibana8,9, Sei-ichiro Watanabe10 and Yuichi Tsuda8
1
US Naval Research Laboratory, Washington DC, USA, 2Carnegie Institution of Washington, Washington DC, USA,
3
Hiroshima Univ., 4Hokkaido Univ., 5Tohoku Univ., 6Kyoto Univ., 7Kyushu Univ., 8JAXA, 9Univ. of Tokyo, 10Nagoya
Univ.
Acid-insoluble, macromolecular organic matter represents up to 4 wt% of the matrix of carbonaceous chondrites(CC). Many properties of the insoluble organic matter (IOM), including microstructure, functional group chemistry,
and mineralogical associations strongly correlate with asteroid parent body grouping and alteration history [1].
However, the IOM of many chondrites shows significant variation in structure, chemistry, and isotopic compositionat the nanoscale [2,3]. The microstructure of CC IOM ranges from discrete sub-micron blebs called nanoglobules; tomicrometer and larger sized veins; diffuse intergranular material; OM intercalated into phyllosilicates, and poorlygraphitized carbonaceous grain coatings. In addition, the IOM can serve as host to inorganic carbonaceous phases,
such as presolar nanodiamond [4] and phase-Q [5]. This variation results from a combination of inherited molecular
cloud chemistry, nebular processing, parent body and terrestrial alteration. Studies of the nanoscale variation in the
IOM in the returned samples of Ryugu provide the first chance to examine the IOM of a CC parent body largely freeof terrestrial alteration signatures, in order to better constrain the alteration history of a specific asteroid, and provide
unprecedented constraint on the evolution of carbon in the early solar system.
Our primary method for the Initial Analysis of the nanoscale diversity of Ryugu IOM microstructure andfunctional chemistry is scanning transmission electron microscopy (STEM), in coordination with scanningtransmission x-ray absorption spectroscopy (STXM), and isotopic characterization with NanoSIMS. The STEM
measurements are carried out with the Nion UltraSTEM 200-X at the Naval Research Lab, operated at 60 kV tominimize electron beam damage. STEM measurements include annular dark field (ADF) imaging, electron energy
loss spectroscopy (EELS), and energy dispersive x-ray spectroscopy (EDS). The EELS and EDS data are collected
as simultaneous spectrum images to allow direct correlation of the elemental composition with the C functional
chemistry, and microstructure [6]. As of this abstract submission, we have examined slices of three grains from
Chamber A (A0108), one prepared as a focused ion beam (FIB) lift-out section, and two prepared as sulfur-embedded
ultramicrotome slices. The FIB section was analyzed with STXM at Photon Factory Bl-19 prior to the STEM analysis.
Adjacent microtome slices of were prepared for coordinated STXM and NanoSIMS measurements at the Advanced
Light Source and Carnegie Institution of Washington, respectively. Measurements of additional FIB and microtome
slices of Chamber A and Chamber C particles are planned.
Overall, our STEM measurements indicate IOM microstructures and functional chemistry consistent with low
temperature aqueous alteration, broadly consistent with CI and CM chondrites. Small nanoglobules (< 400 nm) areabundant, but larger nanoglobules > 1000 nm are less common. Diffuse carbon intercalated into phyllosilicates is also
common. Carbonate and nanoscale Fe, Ni sulfides are also found in association with IOM Coordination of the STEM
results with the ongoing STXM and NanoSIMS measurements of slices from the same grains will ultimately help
constrain the nature of Ryugu and its relationship to known carbonaceous chondrites, and the history of the organic
matter it contains.
References[1] Alexander C. M. O’D. et al. 2017. Chemie der Erde - Geochemistry 77:227. [2] De Gregorio B. T. et al. 2013.
Meteoritics & Planetary Science 48:904. [3] C. Le Guillou et al. 2014. Geochemica et Cosmochemica Acta 131:368. [4] Garvie, L.A.J. (2010), Lunar and Planetary Science Conference, #1388. [5] Amari, S., et al. 2013.
Astrophysical Journal 778:37. [6] Stroud R. M. et al. Microscopy and Microanalysis 27(S1):2546.

Infrared transmission spectra of Ryugu particles and their unique adsorption behavior
Yoko Kebukawa1, Lydie Bonal2, Eric Quirico2, Emmanuel Dartois3, Cécile Engrand4, Jean Duprat5, Jérémie Mathurin6,
Alexandre Dazzi6, Ariane Deniset-Besseau6, Hikaru Yabuta7 and The Hayabusa2-initial-analysis IOM team,
Hisayoshi Yurimoto8, Tomoki Nakamura9, Takaaki Noguchi10, Ryuji Okazaki11, Hiroshi Naraoka11, Kanako Sakamoto12,
Shogo Tachibana12,13, Sei-ichiro Watanabe14 and Yuichi Tsuda12
1
Yokohama National Uni., 2IPAG, Univ. Grenoble Alpes, CNRS CNES 3ISOM, 4IJCLab, 5IMPMC/MNHN, 6ICP, 7Hiroshima
Univ., 8Hokkaido Univ., 9Tohoku Univ., 10Kyoto Univ., 11Kyushu Univ., 12JAXA, 13Univ. of Tokyo, 14Nagoya Univ.
The Hayabusa2 spacecraft successfully obtained samples from two different locations from Ryugu, a C-type asteroid, andreturned them to the Earth on December 6, 2020. The first touchdown samples and second touchdown samples were separately
stored in sample container chamber A and chamber C, respectively. The initial analyses began in June 2021, after curation at
ISAS/JAXA. The insoluble organic matter (IOM) subteam has so far conducted in-situ analyses of the Ryugu particles, inorder to decipher the nature of the organic matter and its origin, parent body processing, and interaction with water andminerals. Fourier transform infrared (FTIR) spectroscopy is a nondestructive technique for functional group chemistry andstructures which is suitable for both organic and inorganic compounds. To date, IR absorption (transmission) spectra have beenobtained from various chondrites and other astromaterials such as interplanetary dust particles (IDPs), micrometeorites andcometary dust particles [e.g., 1-7]. IR spectroscopy is often employed for astronomical observations and remote sensing. The
reflectance spectra of solar system bodies provide information of the compositions of their surfaces. To compare the laboratory
samples and the surfaces of asteroids, IR reflectance spectra have been commonly used [e.g., 8-10]. Both IR transmission andreflectance spectra give intrinsically similar information as both reflect the absorptions of IR frequencies by the target samples,
although some differences do exist. As a part of the initial analysis in the IOM team, IR absorption spectra were obtained using
FTIR microspectroscopy, to provide initial characterization of the Ryugu particles and search for organic matter, as well as forcomparison with the surface reflectance spectra of Ryugu. Several samples were analyzed in parallel in the team, in Japan(Yokohama National Univ., YNU) and in France (IPAG, Grenoble and Orsay-lab teams) to increase the robustness of theanalysis.
Each particle (sub-millimeter in diameter) from the aggregates in chamber A (A0108) or chamber C (C0109), was further
decomposed by gently crushing between two glass slides, or by separation of a fragment with a scalpel. The small fragments
were then further crushed between two diamond windows (YNU and IPAG) and in a diamond compression cell under an
optical microscope to optimize the thickness for further atomic force microscope based infrared spectroscopy (AFM-IR)
measurements (Orsay-lab). In YNU, IR absorption spectra were collected from each diamond window with a micro-FTIR(JASCO FT/IR-6100+IRT-5200), equipped with a ceramic IR light source, a germanium-coated KBr beam splitter, a mercurycadmium-telluride (MCT) detector, and ×16 Cassegrain mirrors, with typically 20 × 20 μm aperture. The microscope and the
FTIR were continuously purged with dry N2. To remove adsorbed water further from the sample, a heating stage (Linkam
10036L) was employed. The IR absorptions from water were satisfactory removed typically by 60 °C under N2 flow. MicroFTIR measurements were also conducted at IPAG with a Hyperion 3000 Bruker FTIR microscope, operating with a ~50 × 50
µm spot and an environmental cell placing the sample under secondary vacuum (< 10 -6 mbar) and gentle heating (< 80° C) toremove adsorbed water. IR spectra by the Orsay-lab team were taken during a week of beamtime at the SOLEIL synchrotron(SMIS beam line). The synchrotron beam was coupled to a Nicolet Continuum 2 IR microscope equipped with a MCT detector
and a ×32 Cassegrain optics, under dry air. For these measurements, the IR spot size was optimized with an aperture of 6 × 6µm, close to the diffraction limit, and hyperspectral maps of Ryugu samples were acquired over several hundreds of µm in size.
The IR absorption spectra of both A0108 and C0109 particles were almost identical, and typically consistent with CI
chondrites. However, some local heterogeneity exists, e.g., IR spectra from some areas were dominated by carbonate features,and opaque minerals are seen in high resolution hyperspectral maps. They display Mg-rich phyllosilicate bands at ~1000 cm-1
(Si-O stretching) and ~3700 cm-1 (OH group in phyllosilicates), organic bands (aliphatic C-H) at 3000-2800 cm-1. The positionand narrowness of the OH band fit those observed in spectra collected in-situ by the spacecraft [11]. Compared to thereflectance spectra obtained by JAXA curation [12], the OH band and aliphatic C-H bands features in the absorption spectra
were roughly consistent, but the abundance of aliphatic C-H peaks were lower than the reflectance spectra. Such differences
could be due to the difference between reflectance spectra and transmission spectra of sample particles. Also, interesting
behavior was observed during FTIR analysis, in that the aliphatic C-H peak increased during analysis for a few hours, likely
due to adsorption of environmental volatile organic compounds (VOCs). It is known that porous OH bearing silicates adsorb

VOCs [e.g., 13-15], particularly when fresh surfaces are exposed by sample crushing [16], however the Ryugu samples appear
unusually reactive and absorb VOC very rapidly, considering that the Ryugu sample analysis was conducted in a clean
environment without abundant contamination sources. This behavior indicates that Ryugu samples are fresh and highly porous.
Measurements conducted under vacuum and gentle heating reveal a rapid and dramatic disappearance of adsorbed water, alongwith an increase of the aliphatic band intensity. This has been previously observed for CI chondrites [6,17,18], and confirms
the high adsorption properties of Ryugu samples. Tight interactions between organics and -OH in phyllosilicates may accountfor this spectral evolution.
Overall, the FTIR organic signatures of the Ryugu samples do not point to a significant post-accretional heating as
observed in heated CM/CI chondrites [19]. Acid extraction of Ryugu samples very soon will provide a fresh IOM isolate, andthereby enable quantitative characterization of chemical group abundances.
References[1] Keller L. P. et al. 2004. Geochimica et Cosmochimica Acta 68: 2577. [2] Osawa T. et al. 2005. Meteoritics & Planetary
Science 40: 71-86. [3] Sandford S. A. et al. 2006. Science 314: 1720. [4] Beck P. et al. 2014. Icarus 229: 263. [5] Dartois E. et
al. 2018. Astronomy & Astrophysics 609: A65. [6] Battandier M. et al. 2018. Icarus 306: 74. [7] Kebukawa Y. et al. 2019.
Meteoritics & Planetary Science 54: 1632. [8] Cloutis E. A. et al. 2011. Icarus 212: 180. [9] Cloutis E. A. et al. 2011. Icarus
216: 309. [10] Cloutis E. A. et al. 2012. Icarus 217: 389. [11] Kitazato K. et al. 2019. Science 364: 272. [12] Yada T. et al.
2021. Nature Portfolio, under review. [13] Pires J. et al. 2001. Microporous and Mesoporous Materials 43: 277. [14] Li X. et al.
2020. Separation and Purification Technology 235: 116213. [15] Zhu L. et al. 2020. Journal of Hazardous materials 389:
122102. [16] Kebukawa Y. et al. 2009. Meteoritics & Planetary Science 44: 545. [17] Beck P. et al. 2010. Geochimica et
Cosmochimica Acta 74: 4881. [18] Takir D. et al. 2013. Meteoritics & Planetary Science 48: 1618. [19] Nakamura T. et al.
2005. Journal of Mineralogical and Petrological Sciences 100: 260.

Thermal history of Ryugu based on Raman characterization of Hayabusa2 samples
Lydie Bonal1, Eric Quirico1, Mutsumi Komatsu2, Gilles Montagnac3, Hikaru Yabuta4 and The Hayabusa2-initial-analysis IOM
team, Hisayoshi Yurimoto5, Tomoki Nakamura6, Takaaki Noguchi7, Ryuji Okazaki8, Hiroshi Naraoka8, Kanako Sakamoto9,
Shogo Tachibana9, 10, Sei-ichiro Watanabe11 and Yuichi Tsuda91Institut de Planétologie et d’Astrophysique de Grenoble, Université Grenoble Alpes, CNRS CNES, Grenoble, France
2
SOKENDAI, The Graduate Univ. for Advanced Studies
3
Laboratoire de géologie de Lyon, CNRS/INSU - ENS de Lyon, Lyon, France
4
Hiroshima Univ., 5Hokkaido Univ.,6Tohoku Univ., 7Kyoto Univ.,8Kyushu Univ., 9JAXA, 10Univ. of Tokyo, 11Nagoya Univ.

Introduction: The degree of structural order of the polyaromatic carbonaceous matter present in extraterrestrial samples is a
tracer of the thermal history they experienced (e.g., primitive chondrites: [1-4]; micrometeorites: [5-6]). To characterize
Ryugu’s thermal history (long vs. short thermal heating and extent of thermal heating), we thus perform Raman
characterization of several Ryugu particles returned by the Hayabusa2 mission. In order to be fully confident in the obtained
data and interpretation, Raman characterization was led independently by two groups of persons in Japan and in France on
distinct Ryugu particles. The results were subsequently compared.
Samples and methods: Raman point analyses were performed on several fragments of six particles from Chamber A
aggregates (A0108) and six particles from Chamber C aggregates (C0109). To be able to combine in situ IR and NanoSIMS
measurements on the same samples, fragments of particles were manually selected under a binocular and pressed onto
diamond windows. The Raman spectra were acquired with a 532 nm laser in both Japan and France. Because some Raman
bands related to carbonaceous matter are dispersive, data for Ryugu particles and comparison samples have been acquired andanalyzed consistently in both Japan and in France. In particular, a Renishaw InVia Reflex equipped with a 1800 l/mm grating
at Materials Characterization Central Laboratory was used in Waseda University (Japan). The laser was focused at the sample
surface through a 50× objective (spot size around 3-4 μm) and its power was set at 0.24 mW and 1 mW. Each acquisition
comprised five integrations of 10 s that were averaged to make the final spectrum. In France, Raman measurements were
performed at the Ecole Normale Supérieure de Lyon (Laboratoire de Géologie de Lyon—Terre, Planètes, Environnement)using a LabRam Raman spectrometer (Horiba Jobin-Yvon) equipped with a 600 g/mm grating. The laser was focused througha 100× objective to obtain a <2 μm spot size. The power on the sample was 0.3 mW. Each acquisition comprised six
integrations of 15 s that were averaged to make the final spectrum.
Results and discussion: More than 200 spectra were acquired on 12 different particles. The Raman data acquired in Japan andin France are fully consistent. Each acquired spectrum is characterized by a high fluorescence background and by the presenceof the Raman D- (~ 1350 cm-1) and G-bands (~ 1580 cm-1), related to the presence of polyaromatic carbonaceous matter. The
spectral parameters derived from the mathematical fitting of the individual spectra, that is, the band widths (FWHM-D,
FWHM-G), the band positions (ωD, ωG), and the band intensity ratio (ID/IG) are comparable between particles. No systematicdifferences have been observed to date between the spectral parameters of Chamber A and Chamber C particles. This point
will be further investigated on insoluble organic matter isolated by acid treatment of Ryugu samples.
The Ryugu particles contain polyaromatic carbonaceous matter that is poorly structured, as reflected by the high fluorescencebackground superimposed to wide D- and G-Raman bands, present at relatively low Raman shifts. The comparison of these
spectral parameters with similarly characterized chondrites shows that the structural order of the polyaromatic carbonaceous
matter present in Ryugu particles is comparable to that in primitive (type 1, type 2) carbonaceous chondrites. Ryugu thus
escaped significant degree of long duration radiogenic thermal metamorphism (as typically experienced by type 3 chondrites),
as well as short-duration heating as experienced by some type 2 chondrites (e.g., [4]).
References[1] Bonal et al. 2006. Geochimica Cosmochimica Acta 70 :1849. [2] Bonal et al. 2016. Geochimica Cosmochimica Acta 189:
312. [3] Busemann et al. 2007. Meteoritics & Planetary Science 42: 1387. [4] Quirico et al. 2018. Geochimica Cosmochimica
Acta 241 : 17 [5] Dobrica et al. 2011. Meteoritics & Planetary Science 46 : 1363. [6] Battandier et al. 2018. Icarus 306 : 74.

Elemental and isotopic compositions of organic grains from asteroid Ryugu
Laurent Remusat1, Maximilien Verdier-Paoletti1, Smail Mostefaoui1, Lydie Bonal2, Hikaru Yabuta3 and The Hayabusa2initial-analysis IOM team, Hisayoshi Yurimoto4, Tomoki Nakamura5, Takaaki Noguchi6, Ryuji Okazaki7, Hiroshi Naraoka7,
Kanako Sakamoto8, Shogo Tachibana8, 9, Sei-ichiro Watanabe10 and Yuichi Tsuda8
1Museum National d’Histoire Naturelle, CNRS, Sorbonne Université, Paris, France. 2Institut de Planétologie etd’Astrophysique de Grenoble, Université Grenoble Alpes, CNRS CNES, Grenoble, France 3Hiroshima Univ., 4Hokkaido
Univ.,5Tohoku Univ., 6Kyoto Univ.,7Kyushu Univ., 8JAXA, 9Univ. of Tokyo, 10Nagoya Univ.

Introduction: Isotope composition of organic material found in extraterrestrial samples is a powerful proxy for tracking its
origin and evolution during the solar system events [1,2]. In situ investigation of isotope and elemental compositions unravel
the heterogeneity and diversity of organic particles embedded within the fine-grained minerals of chondrites and IDPs [3,4].
Understanding the origin of organic matter on carbonaceous asteroids and its subsequent evolution due to secondary processes
as well as space weathering is one of the prime goals of the Hayabusa2 sample-return mission [5]. To document Ryugu’s
inventory of organic material, we have employed NanoSIMS imaging of intact grains, without any chemical treatments, fromboth Chamber A and Chamber C. We present here the first set of data acquired on the NanoSIMS installed at the National
Muséum of Natural History in Paris, and compare the composition of organic particles from the two sampling sites to evaluate
the influence of space weathering and aqueous alteration.
Samples and methods: Several fragments of 3 particles from Chamber A aggregates (A0108) and 3 particles from Chamber C
aggregates (C0109) were manually selected under a binocular and pressed on diamond windows. After their analysis by
Raman and transmission FTIR, samples were gold coated (about 25 nm thick) before NanoSIMS imaging. In the first step,secondary ions of 16O, 12C2, 12C14N, 12C15N and 32S were imaged in multicollection mode, to investigate N-isotope distributions
as well as N/C, O/C and S/C elemental ratios. A 2-3 pA primary Cs+ beam with a spatial resolution around 200 nm wasrastered over 20 by 20 Pm2, divided into 256 by 256 pixels, in association with an electron flooding gun for charge
compensation. Dwell time was set at 2 ms/pixel and about 60 frames were stacked.
Results and discussion: About 11,600 and 9,600 Pm2 surface area were imaged, of Chamber A and Chamber C samples,
respectively. Individual organic particles were identified using the L’image software developed by Larry Nittler (Carnegie
Institution of Washington). The 15N/14N ratios of individual particles are comparable to the values for isotope anomalies in CI
and CM insoluble organic matter [3,6,7] whilst samples from Chamber C tend to exhibit a slightly larger 15N enrichment. In
addition, bulk organic G15N is in the range of IOM in CI chondrites. These values are consistent with independent NanoSIMS
measurements of other Ryugu aggregates [8]. The corresponding elemental ratios point to a larger content in N in the organic
particles from Chamber A, while the particles from Chamber C are more O-rich. Overall, S content is similar in organic
particles from both chambers. It must be noted that O/C and S/C may be biased by the occurrence of fine scale association ofoxides/silicates and sulfides with the organic particles, as observed by TEM [9]. The elemental composition of particulateorganic matter will be further investigated on insoluble organic matter isolated by acid treatment of Ryugu samples. Our datasuggest differences between aggregates from the two sampling sites in terms of elemental and isotope compositions ofindividual organic particles.
References[1] Remusat et al. 2010. ApJ 713:1048. [2] Alexander C. M. O’D. et al. 2017. Chemie der Erde - Geochemistry 77:227. [3]Busemann et al. 2006. Science 312 :727. [4] Remusat et al. 2009 ApJ 698 :2087. [5] Tachibana et al. 2014. Geochem. J.
48:571. [6] Alexander et al. 2010. GCA 74:4417. [7] Remusat et al. 2019. GCA 263:235. [8] Nittler et al. 2021. Thisconference. [9] Stroud et al. 2021. This conference.

Exposure Conditions of Samples Collected on Ryugu’s Two Touchdown Sites Determined by
Cosmogenic Nuclides
Kunihiko Nishiizumi1, Marc W. Caffee2, Keisuke Nagao3, Ryuji Okazaki4, Hisayoshi Yurimoto5, Tomoki Nakamura6, Takaaki
Noguchi7, Hiroshi Naraoka4, Hikaru Yabuta8, Kanako Sakamoto9, Shogo Tachibana9, 10, Sei-ichiro Watanabe9, 11, Yuichi
Tsuda9, and Hayabusa2 Initial Analysis Volatile Team
1
Space Sci. Lab., Univ. of California, Berkeley, CA 94720-7450, USA., 2Dept. of Phys. & Astro., Purdue Univ., West Lafayette,
IN 47907-2036, USA., 3KOPRI, Incheon 21990, Korea, 4Kyushu Univ., Fukuoka 819-0395, Japan, 5Hokkaido Univ.,
6
TohokuUniv., 7Kyoto Univ., 8Hiroshima Univ., 9ISAS/JAXA, 10Univ. of Tokyo, 11Nagoya Univ.
Hayabusa2 arrived at the C-type asteroid 162173 Ryugu in Jun. 2018, and successfully collected surface samples from two
sampling sites, returning ~5.4 g of samples to Earth on Dec. 6, 2020. Surface samples stored in Chamber A were collected by
the 1st touchdown (TD) on Ryugu’s surface on Feb. 21, 2019. A crater (diameter of ~14 m) on Ryugu’s surface was madeusing a collision device - denoted “Small Carry-on Impactor (SCI)” - on Apr. 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 Jul. 11, 2019 [2].
Our studies are based on the measurement of those nuclides produced in asteroidal surface materials by cosmic rays - bothsolar and galactic cosmic rays. Cosmic-ray-produced (cosmogenic) nuclides are used to determine the duration and 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. They are also key to understanding the history of Ryugu’s surface
and asteroid-meteoroid evolutionary dynamics. For Hayabusa2 samples, there are several specific questions we aim to address:(1) are the Chamber C samples, collected during the 2nd touchdown ejecta deposits from the artificial crater, (2) if so, what is theoriginal depth of each recovered sample in the Ryugu regolith, and (3) what is the surface exposure time, mixing rate, anderosion/escape rate of Ryugu’s surface? To answer these questions, we were allocated and received 2 particles from Chamber
A (A0105-19 and -20) and 3 particles from Chamber C (C0106-09, -10, and -11) for measurements of cosmogenic radionuclides
and noble gases. Each sample is several hundred µm in size.
We transferred the individual grains to acid cleaned sapphire containers, with ~2 mm diameter hole, using a vacuum tweezer
at the JAXA curation facility. The five samples were hand carried to the Space Sciences Laboratory (SSL), University ofCalifornia, Berkeley. Each sample was gently crushed by a mortar and pestle made from sapphire and then divided into two
fractions, one fraction for cosmogenic radionuclides and one for noble gases. The samples were individually transferred to asmall 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 from the Al boat and dissolved with a few drops of HF-HNO3 mixture in thepresence of clean Be, Al, Cl, and Mn carriers. After Cl was separated as AgCl, a small analysis aliquot was taken for chemical
analysis by ICP-OES (Table 1). Beryllium and Al were separated by ion chromatography, using 1 mL anion and cation ion
exchange columns, and purified for accelerator mass spectrometry (AMS) measurements. To serve as a baseline comparison,
three grains of the Nogoya CM2 chondrite were analyzed using the same protocols.
Beryllium-10 (t1/2 = 1.36 x 106 yr) AMS analysis was performed at PRIME lab, Purdue University [3] and result was shownin Table 1. Analyses of 26Al (7.05 x 105 yr) and 36Cl (3.01 x 105 yr) as well as noble gases will be done in the near future.
Table 1. Chemical compositions and cosmogenic nuclide 10Be concentration in Hayabusa2 samples and Nogoya CM2 chondrite.
SampleHayabusa2 A0105-19
Hayabusa2 A0105-20
Hayabusa2 C0106-09
Hayabusa2 C0106-10
Hayabusa2 C0106-11
Nogoya CM2
Nogoya CM2
Nogoya CM2

Mass
(mg)
0.24290.20610.12280.15430.18980.45940.34370.2049

Mg
(%)
8.18
8.41
6.05
7.97
8.45
9.96
9.61
11.27

Ti
(ppm)
470
720
690
490
450
480
480
410

Mn
(ppm)
(2010)(2090)
1800
1680
1710

Fe
(%)
17.6
18.0
19.5
21.0
21.5
20.0
19.9
19.8

Co
(ppm)
590
460
580
440
430
580
540
380

Ni
(%)
1.00
1.03
1.36
1.43
1.29
1.18
1.17
1.20

10

Be
(dpm/kg)
12.76 ± 0.37
12.75 ± 0.29
7.10 ± 0.30
7.48 ± 0.26
7.21 ± 0.43
2.09 ± 0.13
2.12 ± 0.09
2.00 ± 0.13

Mn concentrations in parentheses are large uncertainty.

Although the chemical compositions of all 5 Hayabusa2 particles are very similar, the concentrations of Fe and Ni of the 3
Chamber C samples are ~10 % higher than that of Chamber A samples. Our measurements of the 5 Hayabusa2 samples indicatethat the chemical composition of Ryugu is closer to those of CI or CM carbonaceous chondrites, rather than CV or CO.

To validate our procedures we measured the 10Be concentrations in 3 individual grains from Nogoya. The concentrations
from the Nogoya grains are nearly identical and in good agreement with our previous measurement of 2.22 ± 0.10 dpm/kg. The
measurements reported here used ~3 orders of magnitude less sample mass than the measurements made years ago, haveessentially the same uncertainties. For Ryugu, we were able to obtain high quality 10Be measurements using ~100 µg sample.
The surface of Ryugu is bombarded by cosmic ray in a 2π exposure geometry, similar to surface of the Moon. On the Moon,
the production profile of cosmogenic 10Be from the surface to a depth of over 400 g/cm2 is well established by measurements of
10
Be concentrations in the Apollo 15 drill core and 15008/7 core, shown in Fig. 1 [4, 5]. The 10Be concentrations in A0105-19
and -20 are equivalent to the saturation value measured at the surface of the Moon. The simplest scenario is that both A010519 and -20 were collected from a depth of 0-30 g/cm2 on Ryugu. Both samples have been continuously exposed to cosmic ray
at a similar depth for more than several Myr. A more precise depth can be obtained by measurement of 26Al, which has adifferent production profile than 10Be, and is also produced by solar cosmic ray at shallow depth (≤ several g/cm2). Since the10
Be activity is saturated, the total exposure age must be obtained by measurements of longer half-life (3.7 x 106 yr) 53Mn andcosmogenic noble gases. Beryllium-10 concentrations in three Chamber C samples are lower than that of the Chamber A
samples but nearly the same as each other. The sampling location of the 2nd TD is close to the ”ejecta ray 3” described by [1].
Assuming that the Chamber C samples were shielded during their exposure to cosmic rays and then were incorporated into theejecta deposits from the artificial crater by SCI impact, we can calculate the depth at which they were exposed. All three
Chamber C samples were ejected from a depth of 150 – 180 g/cm2 from Ryugu (see Fig. 1). This depth corresponds to 1.3 –1.5 m, assuming the regolith density is the same as Ryugu’s bulk density of 1.2 g/cm3 [6]. Since the depth of the crater floor
from the initial surfaces was determined 1.7 m by a digital elevation map (DEM) [1], three Chamber C samples were ejectedfrom near bottom of the crater. Alternatively, if we assume these were not ejecta, but were resident on the surface, the lower
10
Be activities would indicate that these grains have shorter exposure ages, ~ 1 Myr. Based on their location near the artificial
crater ejecta ray, we consider this scenario unlikely. Aluminum-26 and 36Cl measurements of these samples will further
constrain ejection depth and condition.
For our work, we obtained 5 similar sized, ~0.5 – 1 mm, grains. We don’t know whether the sizes we observe now are
representative of the grain’s original sizes on Ryugu’s surface; it is possible that they were broken during the collection process
or during sample handling. We are certain though that independent of their original size on Ryugu, the three Chamber C grains
were exposed to cosmic rays at the same depth. These grains had ample 10Be for measurement, 10Be measurements are possible
in smaller grain sizes. A logical next step would be the measurement of 10Be in grains of different sizes to investigate whether
any possible association of grain size and ejection depth.
Based on saturated 10Be in surface samples and from ejecta samples we conclude that the surface of Ryugu has been exposed
to cosmic rays for more than several Myr and that the upper 1 - 2 m of regolith have been relatively undisturbed for more thanseveral Myr. Our observation shows that the surface of Ryugu is more stable than the surface of Itokawa and the estimation bygeomorphological indicators [7]. Additional cosmogenic nuclide measurements, especially stable noble gases, will allow adetailed understanding of the surface evolution of Ryugu.
15

Figure 1.
10
Be

10

10

Be (dpm/kg)

10
9
8

Be

The depth profile of 10Be production on the Moon.

Black diamonds indicate 10Be concentration vs. depth on the Moon
measured in undisturbed Apollo 15 drill core and 15008/7 core [4,A0105

5]. Observed 10Be concentrations in Hayabusa2 samples are plot
at estimate depths on Ryugu and marked red circle (A0105) andC0106

square (C0106).

7

References: [1] Arakawa M. et al. 2020. Science 368, 67-71. [2]6Tsuda Y. et al. 2020. Acta Astronautica 171, 42-54. [3] Sharma P.

5

et al. 2000. NIM B172, 112-123. [4] Nishiizumi K. et al. 1984. EPSL
70, 157-163. [5] Nishiizumi K. and Caffee M. W. 2019. MAPS 54,

46087pdf. [6] Watanabe S. et al. 2019. Science 364, 268-272. [7]30Sugita S. et al. 2019. Science 364, eaaw0422.

50

100

150
200
2
Depth (g/cm )

250

300

Acknowledgments: We thank Hayabusa2 project and initial analysis team, especially Hayabusa2 curation members. Z. Nett and K. C. Welten
helped a part of laboratory works. Nogoya was obtained from Field Muse. of Nat. His. This work was supported by NASA’s LARS program.

Small grains from Ryugu: handling and analysis pipeline for Infrared Synchrotron
Microspectroscopy
Stefano Rubino1, Zélia Dionnet1, Alice Aléon-Toppani1, Rosario Brunetto1, Tomoki Nakamura2, Donia Baklouti1, Zahia
Djouadi1, Cateline Lantz1, Obadias Mivumbi1, Ferenc Borondics3, Stephane Lefrançois3, Christophe Sandt3, Francesco
Capitani3, Eva Héripré4, David Troadec5, Megumi Matsumoto2, Kana Amano2, Tomoyo Morita2, Hisayoshi Yurimoto6,
Takaaki Noguchi7, Ryuji Okazaki7, Hikaru Yabuta8, Hiroshi Naraoka7, Kanako Sakamoto9, Shogo Tachibana9-10, Sei-ichiro
Watanabe11, Yuichi Tsuda9, and the Hayabusa2-initial-analysis Stone team1

IAS, Université Paris-Saclay, CNRS, France, 2Tohoku University, Japan, 3SMIS-SOLEIL, FranceCentraleSupélec, Université Paris-Saclay, CNRS, France, 5IEMN, Université de Lille, France, 6Hokkaido University, Japan,
7
Kyushu University, Japan, 8Hiroshima University, Japan, 9ISAS/JAXA, Japan, 10The University of Tokyo, Japan, 11Nagoya
University, Japan

4

Introduction: In December 2020, the sample return mission
Hayabusa2 (JAXA) brought 5.4g of matter from the surface of Ctype primitive asteroid (162173) Ryugu [1]. This extremely
precious material is now the object of multiple studies with stateof-the-art techniques in laboratories all around the world (Initial
Analysis phase). These studies will grant new insight on the origin
and evolution of primitive hydrated planetesimals, and ultimately
on the early stages of our solar system. Within the Hayabusa2initial-analysis “Stone” team [1] led by T. Nakamura, we received
several microscopic particles in July 2021, with the goal of
performing IR hyper-spectral imaging and IR micro-tomography
studies.
Samples transfer and handling: Ryugu samples are kept in acontrolled N₂ environment at Sagamihara (JAXA) in order toFigure 1. Sample-holder description
avoid exposure to the terrestrial atmosphere. We took several steps
in order to minimize the samples’ exposure to air, before, during
and after measurements. Prior to receiving the samples, we designed a custom sample-holder (Figure 1) for transferring particles
from Japan to France and for their preliminary analysis. Particles from Ruygu were deposited on a gold mirror inside the sampleholder at Tohoku University (Japan). A KBr window installed in the cover of the sample-holder allowed us to acquiremeasurements of the particles while the sample-holder was still sealed. This custom-made sample-holder was kept as clean andsterile as possible (to avoid terrestrial contamination) and it had to fulfill two major requirements: fit on the microscope stages
for our IR imaging and microspectroscopy studies and keep the samples in a dry N₂ environment (to avoid alteration from theatmosphere). The sample-holder was assembled inside a glovebox under N₂ atmosphere (ΔP ~ 6 mBar, H₂O = 1.0 ppm, O₂ = 1.2
ppm). Multiple interfaces were used in order to prevent the mixing of the clean N₂ atmosphere and the ambient air (gold gasket,
cleanroom static shielding bags), but also to avoid issues from shocks and vibrations (membrane boxes, foam-padded case).
Once in Sendai, the empty sample holders were opened in a glovebox, and were loaded with 32 microscopic particles from
Ryugu (distributed among four sample-holders: 14 particles from the first touchdown site in SH2 and SH3, and 18 particles fromthe second touchdown site in SH1 and SH4).
To monitor the atmosphere’s changes in our sample-holders, these were accompanied by a “control”-holder, with grains ofolivine and Fe dust (to monitor hydration and oxidation). A second “control”-holder, loaded with drierite (calcium sulfate) andsome Fe dust, was kept in France, to monitor hydration and oxidation when not under dry N₂ conditions.
Samples reception and characterization: Upon arrival at synchrotron SOLEIL (France) in early July, the sample holders were
inspected with a binocular through the KBr windows. We were able to identify at least 24 out of 32 of the original Ryugu
particles, either based on their morphological correspondence with the grains prepared at Tohoku, and/or thanks to their clear IR“Ryugu-like” spectral signatures (mainly the 2.7 µm feature [2]). The particle size range was from 20 to 80 µm, with a particularly
large particle in SH4 larger than 100 µm.
The analytical pipeline started with a full spectral characterization using the IR synchrotron beam while keeping the sampleholder closed, in order to minimize exposure to air. During the first three weeks of July, we analyzed all the identified Ryugu
grains in their sample holders using three different FTIR microscopes: (1) a mid-IR large wavelength range MCT/B-equippedand synchrotron-radiation-fed microscope, (2) a far-IR bolometer-equipped microscope, (3) an FPA-equipped imaging
microscope. Multiple detectors were used to access different wavelength ranges, covering from near-IR to far-IR (1 µm to 35µm). This large spectral coverage allowed us to detect carbonates, organics, and phyllosilicates with different band positions [3].
Most of the IR spectra showed interesting features. Hyperspectral maps in the mid-IR of the individual particles were alsoacquired, in order to assess the compositional heterogeneity at the 5-10 µm scale. A few Raman spectra and maps were alsoacquired on isolated fragments, to assess the presence and structure of endemic organics in Ryugu’s particles and to getcomplementary information on the mineralogy.

Thanks to a Raman measurement on a µm-spot on the gold substrate, we managed to detect remotely molecular oxygen inside
SH2, which indicates the holders at some point lost their air-shut condition, probably in flight from Japan to France. We estimatethat the grains were exposed to air for about 72-96 hours, before we received them and we put them again into a dry N2
environment. However, we did not observe any modification of the KBr (a control KBr window we exposed to air for 24h
showed clear modifications), and the anhydrous control samples we sent along the Ryugu sample holders showed no evidenceof water adsorption nor hydration. So we inferred that Ryugu grains remained in a relatively dry environment, although inpresence of O2, probably thanks to the presence of desiccants that prevented an increase in humidity.
In mid- and late-July, we opened sample holders SH2 and SH3, and we mounted 6 Ryugu grains on W or Al needles using two
different FIB-SEM microscopes in Saclay and in Lille [4]. These grains were then measured in both transmission and reflectancemode, by Infrared Computed Tomography [5] (IR-CT) and Infrared Surface Imaging [6] (IR-SI) respectively. IR-CT allows us
to assess the compositional heterogeneity of small particles in a 3D space, while IR-SI allows us to assess the surface composition
for larger particles, treating the grain as a planetary surface by projecting the 2D IR hyper-spectral maps on a 3D shape model.
Data processing and analysis of this large set of data is still ongoing. Our primary method of analysis, IR spectroscopy, is totally
non-destructive, which implies that after our measurements a few particles can be sent to other analytical teams in the scope of
combining different studies on the same sample. Some of these particles are now being analyzed by X-ray computed tomography
at SPring-8 (Japan) [7].
Overall, the outcome of the last months has shown that the agreed handling, transfer and analysis pipelines are valid and may be
applied for future sample-return missions.
Acknowledgements: We thank Moe Matsuoka for her precious help in preparing and sending Ryugu’s particles from SendaiJapan all the way to Orsay-France. This work is part of the multi-analytical sequence of the Hayabusa2 “Stone” MIN-PET group,
led by Tomoki Nakamura. Zélia Dionnet was supported by a CNES postdoctoral allocation and this work was supported by theCentre National d’Etudes Spatiales (CNES-France, Hayabusa2 mission). The micro-spectroscopy measurements were supported
by grants from Region Ile-de-France (DIM-ACAV) and SOLEIL.
References[1] T. Nakamura et al., abstract in this volume ; [2] K. Kitazato et al., Science, 2019, 364, 272–275. ; [3] Z. Dionnet et al, abstract
in this volume ; [4] A. Aléon-Toppani et al., Meteorit. Planet. Sci., 2021, 56, 1151–1172. ; [5] Z. Dionnet et al. 2020. Meteoritics& Planetary Science 55 ; [6] Z. Dionnet et al., in preparation, 2021. ; [7] A. Tsuchiyama et al., abstract in this volume.

Preliminary results from FTIR hyper-spectral imaging campaign on Ryugu small grains andfragments.
Zélia Dionnet1, Stefano Rubino1, Alice Aléon-Toppani1, Rosario Brunetto1, Tomoki Nakamura2, Donia Baklouti1, Zahia
Djouadi1, Cateline Lantz1, Ferenc Borondics3, Christophe Sandt3, Eva Héripré4, David Troadec5, Megumi Matsumoto2, Kana
Amano2, Tomoyo Morita2, Hisayoshi Yurimoto6, Takaaki Noguchi7, Ryuji Okazaki7, Hikaru Yabuta8, Hiroshi Naraoka7,
Kanako Sakamoto9, Shogo Tachibana9-10, Seiichiro Watanabe11, Yuichi Tsuda9 and the Hayabusa2-initial-analysis Stone team.
1

IAS, Université Paris-Saclay, CNRS, France, 2Tohoku University, Japan, 3SMIS-SOLEIL, FranceCentraleSupélec, Université Paris-Saclay, CNRS, France, 5IEMN, Université de Lille, France, 6Hokkaido University, Japan,
7
Kyushu University, Japan, 8Hiroshima University, Japan, 9ISAS/JAXA, Japan, 10The University of Tokyo, Japan, 11Nagoya
University, Japan

4

Introduction: Hayabusa2 is the first sample return mission to study and return samples from a primitive carbonaceous
asteroid. It thus allows the study of the same small body at very different scales, from the km down to the atomic scale. Infrared(IR) spectroscopy plays a crucial role in this respect, helping to build a bridge between the remote sensing observations of theasteroid’s surface, performed by NIRS3 [1,2] and the chemical and physical processes operating at a smaller scale andcharacterized in the laboratory on the returned samples. In December 2020, the Hayabusa2 reentry capsule delivered 5.4 g ofmaterial coming from asteroid Ryugu. This extremely precious material was then recovered by JAXA and pre-characterized
inside the ISAS curation facility [3,4]. A fraction of this material was then given to six Initial Analysis sub teams, including the“Stone” team led by T. Nakamura which studies mineralogy and petrology at a large scale [5].
Material and Methods: We will present the result of FTIR hyperspectral imaging on six micrometric Ryugu fragments(ranging from 30 to 80 µm in size). These fragments originate from 2 bigger millimetric grains (A0064 and C0046). We analyzed
these small grains in multiple configurations (see detailed analytical plan and transportation issues in [6]). After the firstcharacterization in reflectance mode on their gold substrate, we mounted these small grains at the top of metallic needles toanalyze them at different rotating angles both in transmission and reflection modes. The obtained data in transmission mode, IRCT [7] (Infrared Computed Tomography), were then analyzed to reconstruct 3D distributions of the molecular components inside
the grains, while reflectance data were projected on a 3D shape model of the grains. In this case, the fragments were treated as aplanetary surface, which will also help to reinforce the link between remote sensing and laboratories measurements. Taking
advantage of each configuration, the preliminary results of the combination of the different measurements will be shown anddiscussed.
Results and Discussion: We will present the average spectra in the 2.5 – 30 µm range. Several grains have IR signaturesat 2.7 µm, 3.0-3.1 µm, 3.4 µm, and 3.9 µm, in a good agreement with the bands identified by NIRS3 or by MicrOmega and FTIR
in the JAXA curation facility [3, 4], plus several mid-IR signatures of great interest, such as bands attributed to Si-O stretchingin phyllosilicates, and C=O stretching in organics and carbonates. A comparison of the IR spectra of the different grains withthose of a large variety of carbonaceous chondrites acquired with the same set-up will be presented. Finally, we will discuss theheterogeneity within individual grains, with particular emphasis on the following issues: (i) detection and heterogeneity of the
2.7 µm band (ii) spatial correlation between phases (phyllosilicates, carbonates, opaque phases, organics) and (iii) identificationand quantification of the carbonates. These spectral observations and parameters will help to better constrain the 3D μm-scaleassembly of minerals and organics in Ryugu, and will provide information on the origin and evolution of Ryugu.
Perspectives: Our multi-analytical sequence started with non-destructive IR hyperspectral imaging and continues now
with more destructive techniques. One grain has been sliced into 3-µm thin sections and will be analyzed in 2D with higher
resolution IR hyperspectral imaging and complementary analyses [8]. The rest of the samples have been sent back to Japan, tobe analyzed at the BL47XU of SPring-8 synchrotron by XCT [9] in order to obtain complementary information concerning the3D physical, chemical and morphological properties.
Acknowledgments: We thank Moe Matsuoka for her precious help in preparing and sending Ryugu’s particles from
Sendai-Japan all the way to Orsay-France. This work is part of the multi-analytical sequence of the Hayabusa2 “Stone” MINPET group, led by Tomoki Nakamura. Zélia Dionnet was supported by a CNES postdoctoral allocation and this work was
supported by the Centre National d’Etudes Spatiales (CNES-France, Hayabusa2 mission). The micro-spectroscopy
measurements were supported by grants from Region Ile-de-France (DIM-ACAV) and SOLEIL.
References: [1] Kitazato et al. 2019 Science 364-6437: 272. [2] Watanabe, S.-I., Tsuda, Y., Yoshikawa, M., et al. 2017,
Space Science Review, 208: 3. [3] Bibring et al. 2021. Metsoc Abstract #6276. [4] Yada et al. 2021. Metsoc Abstract #6186. [5]Nakamura et al. in this volume. [6] Rubino et al. in this volume. [7] Dionnet et al. 2020. Meteoritics & Planetary Science 55:
1645-1664. [8] Aléon-Toppani et al. 2021. Meteoritics & Planetary Science. [9] Tsuchiyama A. et al. 2011. Science 333-6046:
1125.

Iron valence state and mineralogy in particles from asteroid Ryugu
Jean-Christophe Viennet1, Mathieu Roskosz1, Pierre Beck2, Esen Ercan Alp3, Barbara Lavina3,4, Michael Hu3, Jiyong Zhao3,
Tomoki Nakamura5, Kana Amano5, Mizuha Kikuiri5, Tomoyo Morita5 Hisayoshi Yurimoto6, Takaaki Noguchi7 Ryuji
Okazaki8 Hikaru Yabuta9, Hiroshi Naraoka8, Kanako Sakamoto10, Shogo Tachibana10 ,11, Seiichiro Watanabe12, Yuichi
Tsuda10, and the Hayabusa2-initial-analysis Stone team.
1

Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Museum National d’Histoire Naturelle, CNRS,
Sorbonne Université, Paris, France. 2Institut de Planétologie et d’Astrophysique de Grenoble, Université Grenoble Alpes,
CNRS CNES, Grenoble, France. 3Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637,
USA.4Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA. 5Tohoku Univ. 6Hokkaido
Univ.7Kyoto Univ. 8Kyushu Univ. 9Hiroshima Univ. 10JAXA. 11Univ. of Tokyo, 12Nagoya Univ.
Introduction: Iron is a major element in rocky material from the solar system that can occur under multiple valence state. As
such it can be used to trace geological processes that occurred on asteroid Ryugu, including thermal metamorphism andaqueous alteration. Observations of the mineralogy of carbonaceous chondrites have revealed the presence of minerals
assemblages that are barely in thermodynamic equilibrium. Even at the micron-scale, iron is often present under multiple
valence state (most frequently 0, +2, or +3) in a wide range of minerals (primary or secondary in nature), including silicates,
oxy-hydroxide, sulfides, sulfates, clay minerals and carbonates. Such heterogeneous assemblages are the results of postaccretion processes that often triggered a partial textural and chemical equilibration, associated to a modification of primaryFe-bearing minerals and their valence state. It is therefore tricky to disentangle the different processes recorded by the ironmineralogy of chondritic materials. Furthermore, since most Fe-bearing phases are redox-sensitive, exposure to terrestrial
atmosphere may also induce iron oxidation and additional, late modifications of the iron mineralogy. In this context,
Hayabusa2 sampled Ryugu, an asteroid that did not suffer extensive thermal metamorphism, and returned rocks to Earth withminimal air exposure. It offers a unique opportunity to study the redox state of carbonaceous asteroids and evaluate the overall
redox state of the most oxidized primitive rocks of the solar system.
Samples and methods: Here, we determine the mineralogy and the redox state of Fe-bearing minerals from ten Ryugu
samples (five from the chamber A used for the first sampling and five from the chamber C for the second sampling) prior toand after exposure to air. We use Synchrotron Mössbauer Spectroscopy (SMS) technique that enables to probe the bonding
environment of iron at the microscopic scale. These measurements are combined with co-aligned X-ray diffraction, permitting
to assess locally the mineralogy and valence state of iron in Ryugu particles. We also apply conventional Mössbauer
spectroscopy on a couple of large (mm-size) Hayabusa returned samples from the chambers A and C.
Results and discussion: We will present the bulk proportions of iron-bearing minerals and the Fe redox state (Fe3+/Fetot) at the‘Stone’ scale. We will then provide the first estimate of the redox state of Ryugu as compared to the large array of bulk redox
data collected over several decades on meteorites. We will also describe the redox states of iron-bearing clay minerals before
any air contamination. The first clues on the ageing of these minerals after exposure to air will be discussed based on datacollected on the same sample before and after exposure to air. We will compare in greater details Ryugu samples to a series ofwell-known chondritic meteorites including Orgueil and Murchison. We will show, more specifically, that most of the iron isaccommodated in magnetite and sulfides (pyrrhotite and pentlandite). Clay minerals also contain a fraction of the total iron.
Overall, the investigated Ryugu samples appears to be (or are) more reduced than the Orgueil, both considering the bulk
composition and the clay minerals fraction. The redox state recorded in a pristine sample and in the same sample exposed to air
for more than two months do not show clear evidence of oxidation suggesting that, as far as iron is concerned, samples can beprepared and analyzed at ambient conditions at least for several weeks if stored in vacuum or in inert gas after preparation.

Three-dimensional analysis of Ryugu sample particles using X-ray nanotomography.
Akira Tsuchiyama1,2, Megumi Matsumoto3, Junya Matsuno1, Tomoki Nakamura3, Takaaki Noguchi4,5, Kentaro Uesugi6,
Akihisa Takeuchi6, Masanori Yasutake6, Miyake Akira4, Shota Okumura4, Yuri Fujioka3, Mingqi Sun2, Aki Takigawa7,
Toru Matsumoto4, Satomi Enju8, Itaru Mitsukawa4, Yuma Enokido3, Tomoyo Morita3, Naoto Nakano4 and Stefano Rubino9,
Tsukasa Nakano10 Hisayoshi Yurimoto11, Ryuji Okazaki12, Hikaru Yabuta13, Hiroshi Naraoka12, Kanako Sakamoto14,
Shogo Tachibana7,14, Seiichiro Watanabe15 and Yuichi Tsuda14, and the Hayabusa2-initial-analysis Stone and Sand teams
1Research Organization of Science and Technology, Ritsumeikan University, 2CAS, Guangzhou Institute of Geochemistry,
3Guraduate School of Science, Tohoku University, 4Guraduate School of Science, Kyoto University, 5Faculty of Arts andScience, Kyushu University, 6SPring8/JASRI, 7Guraduate School of Science, University of Tokyo, 8Guraduate School of Scienceand Engineering, Ehime University, 9Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 10GSA/AIST,
11Guraduate School of Science, Hokkaido University, 12Guraduate School of Science, Kyushu University, 13Guraduate Schoolof Advanced Science and Engineering, Hiroshima University, 14ISAS/JAXAWe have performed initial analysis of samples returned from asteroid 162173 Ryugu by the Hayabusa2 spacecraft usingsynchrotron radiation-based X-ray nanotomography to elucidate the 3D structures and features of the samples with sub-micron
spatial resolution as parts of the Hayabusa2 initial analysis Stone and Sand sub-teams.
We analyzed 29 and 20 particles from the first and second touchdown sites (chambers A and C), respectively. Particles of
10 ~ 150 µm in apparent size were picked up and attached to the tips of Ti needles with Pt deposition using FIB or amorphous
carbon fibers with glycol phthalate. They were imaged by two different methods (dual-energy tomography (DET) [1] andscanning-imaging X-ray microscopy (SIXM) [2]) at BL47XU of SPring-8 [3]. In DET, X-ray absorption contrast images wereobtained as the spatial distribution of linear attenuation coefficient (LAC) at two different X-ray energies of 7 and 7.35 keV,which are below and above the K-absorption energy of Fe (7.11 keV), respectively. The LAC images at 7 keV correspondclosely to compositional (Z) contrasts, except for Fe, and those at 7.35 keV strongly depended on Fe content. In SIXM, we
obtained X-ray differential phase contrast images as the spatial distribution of refractive index decrement (RID), which is thedifference between the X-ray refractive index (RI) and unity (RI = 1 - RID), at X-ray energy of 8 keV. The RID image isclosely proportional to the density of the object. The voxel sizes of LAC 7 keV, LAC 7.35 keV and RID images are 47.4
47.447.4 nm3, 51.151.151.1 nm3 and 111.1111.1109.2 nm3, respectively.
The image analysis was made by combining ImageJ and codes made with C and Python. The registration among the three
types of images was made with the reference of LAC 7 keV images. Then, RGB-CT images were made by assigning blue, red,and green to LAC 7 keV, LAC 7.35 keV, and RID images, respectively. Different phases including organic materials show
different colors in the RGB-CT images. Minerals are quantitatively discriminated by comparing the LAC and RID values ofthe objects in CT images and those of minerals with known chemical compositions and densities. The solid portions of thesample particles images were extracted in LAC 7.35 keV using Chan-Base segmentation. The volume, V, surface area, S, 3axial lengths, A≥B≥C, fractal dimension, FD, and closed porosity, p0, were then obtained. Porosity by considering pores andcracks that are open to the outside, named as open porosity, p∞, were also estimated by a wrapping method [4]. The density, r,
was estimated from the averaged RID value of the particle as the lower limit. Density considering open pores, r∞, wascalculated as r(1- p∞). Sphere-equivalent diameter, D, was calculated from V and sphericity, Y, from V and A.
No distinct difference between the samples from chambers A and C was recognized. The sample particles are mainlycomposed of Mg-rich phyllosilicates (serpentine and/or saponite; Mg#~0.8-0.9) in the matrix (Fig. 1A). The phyllosilicates are
not homogeneous in some particles (Fig. 1B) probably due to the difference of Mg# and/or nanoporosity below the spatial
resolution. FeS (mostly pyrrhotite and minor pentlandite) grains are commonly present as hexagonal plates shown as arectangle shape in a slice image (Fig. 1A). We found whiskers of probably FeS (Fig. 1C) in some matrices as well. Magnetite
grains with different morphologies (framboidal, spherulitic, plaquette and equant) are also commonly present (Fig. 1A). Submicron grains of FeS and magnetite are usually present in the matrix. Dolomite is usually present mostly as aggregates ofeuhedral or subhedral grains (Fig. 1A) and contains minor amounts of Fe and some heavy element (possibly Mn). Aggregatesof micron-sized dolomite grains are also present (Fig. 1B). Breunerite is present as a rhombohedron in shape and have thecomposition roughly estimated as (Mg0.6Fe0.4)CO3 (Fig. 1D). CaCO3 (aragonite or calcite) is rarely present. Apatite is usuallypresent mostly as aggregates of subhedral or anhedral grains (Fig. 1E). Small grains of forsterite or enstatite (Mg#~1) arerarely observed. Small objects (mostly <1 µm) of probably organic materials are commonly present in the matrix (Fig. 1B) but
their abundance is small (probably a few % or less). Inclusions, which are empty or filled with low-Z materials, were observedin FeS, dolomite, breunerite and apatite grains (Fig. 1D). Spherical objects of phyllosilicate surrounded by fine grains of FeS

or dolomite (Fig. 1E) and object composed of Fe-rich and mostly anhydrous silicates (Fig. 1E) and fine grains of FeS and/or
magnetite named “dark inclusion” (Fig. 1A) were sometimes observed. In addition to the above phases, several unidentified
phases are observed as well. Some sample particles are unique; a low-density material (~1 g/cm3) with a lot of fine cracks andorganic-like material with embedded mineral grains. Porous objects like the ultra-porous lithology in Acfer 094 [3] were notobserved.

Figure 1. RGB-CT images of Ryugu particles(R: LAC at 7 keV = 0-950 cm-1, G: RID = 02010-6, B: LAC at 7.35 keV = 0-450 cm-1).
(A) C0103-FC007. (B) A3_MPF_X003
showing dark and bright matrices (upper andlower regions, respectively). (C)A3_MPF_X007 showing a whisker ofprobably FeS. (D) A0067-FC0003: breunerite
grain with inclusions. (E) A3_MPF_X007
having wide cracks. (F) A3_MPF_X004.

D ranges from 9 to 60 µm. The 3D shape distribution indicates that the
Ryugu particles (B/A =0. 66 and C/B =0.65 in average) are less spherical inshape than the Itokawa particles and fragments of impact experiments (c.f.,silver ratio: B/A=C/B=0.71) [1]. Some particles examined here may not be theoriginal impact fragments on the Ryugu surface but artificial fragments during
the sampling by the space craft and/or in the laboratory. Y is small (<0.4) and
FD of some particles are <3 together with a weak correlation between them,
indicating that the particle shapes are irregular and complicated. Some surfacesof the particles are convexo-concave indicating fragmentation, while some are
more or less smooth and may be formed by mechanical abrasion on the asteroid
as proposed for Itokawa particles [4]. Cracks less than a few µm in width arecommonly present in all particles except for those composed of single crystals.
Some cracks develop along the boundaries of some objects and mineral grains
Figure 2. Density, r, estimated from the(Fig. 1E), implying that they are cracks formed due to shrinkage by
averaged RID value (lower limit) and density
dehydration. Some cracks are subparallel to flattened particle surfaces
considering open pores, r∞, plotted against
open porosity, p∞.
probably due to impact (Fig. 1F). p0 is usually less than a few%. p∞ mostly
ranges from 5 to 20% (Fig. 2), which is less than the porosity of the CI
chondrite Orgueil (34.9% [5]). This can be explained by the different size of pores; the p∞ counts relatively large pores (>~afew hundred nm) while that of CI counts nanopores. r mostly ranges from 1.3 to 1.8 g/cm3 and and r∞ from 1.1 to 1.6 g/cm3(Fig. 2). They are not inconsistent with the bulk density of Orgueil (1.57 g/cm3 [5]) if we consider r and r∞ as the lower limits.
The examined samples closely resemble CI in mineralogy and textures although we did not surely find any sulfates, such as
gypsum, epsomite and blödite. The porosity and density are also consistent with those of CI. Any signature of dehydration as
suggested from the IR spectrum [6] was not recognized. Highly porous materials as expected from the low thermal inertia [7]were not observed. FIB sections were prepared based on the 3D information and examined by TEM [8, 9]. The present
examination is ongoing and we note that some of the ranges of physical properties, such as D, B/A, C/B, Y, FD, p0, p∞, r and
r∞, are still preliminary.
References[1] Tsuchiyama A. et al. 2013. Geochim. Cosmochim. Acta 116;5. [2] Takeuchi A. et al. 2014. J. Synchrotron Radiat. 20:793.
[3] Matsumoto M. et al. 2019. Science Advances 5;eaax5078. [4] Tsuchiyama A. et al. 2011. Science 333;1125. [5] Flynn G. J.
et al. 2018. Chemie der Erde 78: 269. [6] Kitazato K. et al. 2019. Science 268:272. [7] Okada T. et al. 2020. Nature 579:518.
[8] Nakamura T. et al. 2021. Abstract in this volume. [9] Noguchi T. et al. 2021. Abstract in this volume.

Surface morphologies and space weathering features of Ryugu samples
T. Matsumoto1, T. Noguchi1, A. Miyake1, Y. Igami1, M. Haruta1, H. Saito2, S. Hata2, Y. Seto3, M. Miyahara4, N. Tomioka5, H.
A. Ishii6, J. P. Bradley6, K. Ohtaki6, E. Dobrică6, T. Nakamura7, M. Matsumoto7, A. Tsuchiyama8, 9; M. Yasutake10, J.
Matsuno8, S. Okumura1, K. Uesugi10, M. Uesugi10, A. Takeuchi10, M. Sun9, S. Enju11, A. Takigawa12, H. Leroux13, C. Le
Guillou13, D. Jacob13, M. Marinova13, F. de la Peña13, F. Langenhorst14, D. Harries14, P. Beck15, T. H. Van Phan15, R. Rebois15,
N. M. Abreu16, T. Zega17, P.-M. Zanetta17, M. Thompson18, M. Lee19, L. Daly19, P. Bland20, R. Stroud21, K. Burgess21, J. C.
Bridges22, L. Hicks22, M. E. Zolensky23, D. R. Frank6, J. Martinez24, H. Yurimoto25, K. Nagashima6, N. Kawasaki25, R.
Okazaki2, H. Yabuta4, H. Naraoka2, K. Sakamoto26, S. Tachibana12, S. Watanabe27, Y. Tsuda26, and the Hayabusa2 Initial
Analysis Team1
2
3
Kyoto Univ., Japan; Kyushu Univ., Japan; Kobe Univ., Japan; 4Hiroshima Univ., Japan; 5Kochi Core Center, JAMSTEC,Japan; 6Univ. of Hawaii, USA; 7Tohoku Univ., Japan; 8Ritsumeikan Univ., Japan; 9Guangzhou Institute of Geochemistry,
China; 10JASRI, Japan; 11Ehime Univ., Japan; 12Univ. of Tokyo, Japan; 13Univ. de Lille, France; 14Univ. of Jena, Germany;
15
Univ. Grenoble Alpes, France; 16Penn State, USA; 17Univ. of Arizona, USA; 18Purdue Univ., USA; 19Univ. of Glasgow, UK;
20
Curtin Univ., Australia; 21US Naval Research Laboratory, USA; 22Univ. of Leicester, UK; 23JSC/NASA, USA; 24Jacobs
Engineering, 25USA, Hokkaido Univ., Japan; 26JAXA/ISAS, Japan; 27Nagoya Univ., Japan
Introduction: Asteroids are leftover remnants of planet formation and provide clues as to the origin and evolution of the earlysolar system. C-type asteroids have been expected to be parent bodies of carbonaceous chondrites, containing hydrated silicatesand volatile compounds that could be the origin of water and life on the Earth. JAXA’s Hayabusa 2 spacecraft explored C-type
asteroid Ryugu and collected surface materials at two landing sites on Ryugu [1]. The spacecraft delivered its re-entry capsuleto the Earth, and subsequent initial investigation of the Hayabusa 2 sample container found that millimeter pebbles and finegrains were successfully recovered from the surface of Ryugu [2]. Geologic maps and variations in the reflectance spectra of
Ryugu’s surface suggest that geologic activities and alteration of regolith occur over time [3]. Ryugu samples will provide an
opportunity to understand the dynamic evolution of surface materials on C-type asteroids. Materials exposed to the spaceenvironment are expected to have altered optical, physical, or chemical properties. This process is defined as space weathering,which includes alteration by micrometeoroid bombardments, solar wind implantation, and solar radiation heating [4]. Analysesof lunar soils and regolith particles from S-type asteroid Itokawa have revealed that the uppermost surfaces of regolith grains
record the space weathering features, such as amorphization, melting, and vapor-deposition [5,6]. Thus far, the space weatheringof carbonaceous asteroids is not well understood. The surface microstructures of Ryugu samples will offer insight into theongoing alteration of the regolith on Ryugu. In this study, we report the surface morphologies and mineral structures of Ryugu
samples investigated in the initial analysis by the Mineralogy-Petrology Fine (Sand) sub-team.
Samples and methods: Ryugu samples from the two sampling sites were preserved in chambers A and C of the sample catcher
inside the sample container [2]. We have mainly investigated the fine grains (< 300 µm) picked up from both chambers at theExtraterrestrial Sample Curation Center of JAXA. After the samples were allocated from JAXA, we handled them in a dry glove
box filled with nitrogen at Kyoto University. For surface observation, the fine grains were fixed on gold plates using an Araldite
adhesive. We examined the surface features of the Ryugu samples using a field emission scanning electron microscope (FESEM: JSM-7001F). We then extracted electron-transparent sections of regions of interest on the Ryugu grains fortransmission/scanning transmission electron microscopy (TEM/STEM) studies, using a focused ion beam (FIB) system (Helios
NanoLab G3 CX at Kyoto University, Thermo Scios at Kyushu University). We are now performing TEM/STEM analysis,
synchrotron radiation X-ray absorption fine structure analysis, nano-tomography, and atom probe analysis.
Results: Surface features of Ryugu grains: Fine Ryugu grains have massive, platy, and granular shapes. The majority of thegrain surfaces consist of phyllosilicates with rough surfaces. Coarse and fine surface textures are identified on the phyllosilicates.
Cracks/gaps exist between phyllosilicates and other mineral phases. TEM analysis shows that the phyllosilicates are composed
mainly of serpentine and saponite (detailed TEM observations are described in [7]). The second major mineral phases on thegrain surfaces are sulfides, magnetite, and carbonates. These minerals are ubiquitous, although their abundance varies from grain
to grain. Most of the sulfides are pyrrhotite crystals. They appear as hexagonal plates, cuboids, and irregular shapes with sizes
up to a few tens of micrometers. The pyrrhotite plates exhibit sharp growth steps on their surfaces. Some pyrrhotite crystals withirregular surfaces have numerous voids. Pentlandite often coexists with pyrrhotite. Tiny sulfides (< 1µm), including zinc,
chromium, and/or copper, occur as minor phases. Magnetite appears as framboidal aggregates, plaquettes, spherulites, andirregular shapes. The framboidal magnetite on Ryugu grains have distinct sharp edges, when compared to framboidal magnetites

with rounded morphologies in thermally metamorphosed CI chondrites (e.g., Y980115) in which thermal sintering has likely
occurred. The carbonate phases found on the Ryugu grains are mainly dolomite and minor magnesite-breunnerite. They haveeuhedral, fractured, and irregular surfaces. Calcium phosphate, oxides (chromite, ilmenite), and iron phosphides are found as
minor phases. Na-Mg bearing phosphate with an irregular shape is present as a rare phase and is commonly attached loosely to
the grain surfaces. Anhydrous minerals found on Ryugu grains are forsteritic olivine, low-calcium pyroxene and pure spinel withsizes up to a few micrometers. These phases are rare. Most of them have fractured surfaces.
Space weathering features: We found impact craters, melted drops, splashes, melt sheets, glassy spherules on Ryugu grains
by SEM observation (Fig. 1). Studies of lunar soils and Itokawa particles have shown that these objects are likely products of
micro-impacts on airless bodies [8, 9]; hence, the grain surfaces with the impact products may have been exposed to the spaceenvironment. The abundance of the impact products varies from grain to grain. Phyllosilicates on the grain surfaces are altered
to have smooth surface textures with tiny voids (Fig. 1 in [7]). TEM analysis shows that the uppermost surface is surrounded byan amorphous rim with a thickness from 50 nm to 2-3 µm. Tiny vesicles and iron compounds appear in the rim. EDX analysis
shows a change in chemical composition near the surface. The altered surfaces of pyrrhotite and pentlandite have shallow
depressions (200 nm – 300 nm in depth) with rugged textures (Fig. 1). Iron metals protrude from the iron sulfide surfaces, andsome are in the form of curved whiskers (Fig. 1). Dark-field TEM imaging suggests disordering of the lattice near the sulfide
surface. Carbonates and magnetite have altered surfaces with rough textures. The breunnerite grain we examined by TEM has adistinct rim with disordered lattice and a thickness of approximately 90 nm. Selected area diffraction patterns obtained from therim imply the appearance of periclase ((Mg,Fe)O) particles in the rim.
Discussion: The dominance of phyllosilicates and the scarcity of anhydrous minerals indicate that Ryugu samples haveexperienced a high degree of aqueous alteration. The morphologies of the major mineral phases, such as the unique shapes ofmagnetite, suggest a close similarity between Ryugu samples and CI chondrite [10].
Previous ion irradiation experiments simulating space weathering suggest that the uppermost surface of phyllosilicates canbe modified by space weathering [11]. The altered phyllosilicate rim found in our analysis may have been formed by solar windimplantation and impact events [7]. Iron metallic whiskers on iron sulfides have recently been identified as space weathering
products in lunar soils and Itokawa particles [12,13]. The iron metals are likely to have formed via selective sulfur loss,
accumulation of excess iron atoms, and subsequent growth of iron metals. These alteration processes may be caused by various
phenomena including solar wind implantation, thermal effects produced by micrometeoroid bombardments and solar heating[12]. The appearance of iron whiskers on Ryugu samples implies that the space weathering of iron sulfides on Ryugu is similar
to that on the Moon and Itokawa. The thickness of the altered rim on breunnerite is roughly consistent with the maximum depth
at which extensive atomic displacement is produced by implanted solar wind ions (~ 1 keV/nucleon) [6]. Hence, solar windimplantation may have contributed to the rim formation of the carbonate. Based on our initial analysis, we tentatively conclude
that the Ryugu samples record the combined processes of space weathering on the aqueously altered asteroid, implying that
remote sensing data should be reassessed considering the space weathering effect.

Fig. 1 Space weathered Ryugu grain. (a) Backscattered electron image of a fine Ryugu grain. (b-d) Secondary electron images of a melted
drop (b), pyrrhotite with an iron whisker (c), and an impact crater with a residue on phyllosilicates (d). The image (d) was obtained fromanother fine Ryugu grain. M: melted drop, Po: pyrrhotite, W: iron whisker. Triangles in (d) indicate the crater rim.

References: [1] Watanabe S. et al. 2019. Science 364, 268-272. [2] Yada T. et al. 2021. Abstract# 2548 in 52nd LPSC. [3] Sugita
S. et al. 2019 Science 364, 252. [4] Pieters C. and Noble S. K. 2016. J. Geophys. Res. Planet 121, 1865-1884. [5] Keller L. P.
and McKay D. S. 1993 Science 261, 1305-1307. [6] Noguchi T. et al. Science 333, 1121-1125. [7] Noguchi T. et al. this
symposium. [8] McKay D. S. et al. 1991. Lunar Sourcebook. [9] Matsumoto T. et al. 2018. Icarus 303, 22-33. [10] Brearley A.
2006, Meteorites and the early solar system II, 587-624. [11] Thompson M. et al. 2020. Icarus 346, 113775. [12] Matsumoto T.
et al. 2020. Nat. Commun. 11, 1-8. [13] Matsumoto T. et al. 2021. Geochim. Cosmochim. Acta 299, 69-84.

CNHOS contents with their isotopic compositions and preliminary organic profiles
from the Hayabusa2 samples
Yoshinori Takano1, Hiroshi Naraoka2, Nanako O. Ogawa1, Yasuhiro Oba3, Toshiki Koga1, Toshihiro Yoshimura1,
Saburo Sakai1, Naohiko Ohkouchi1, Hisayoshi Yurimoto3, Tomoki Nakamura4, Takaaki Noguchi5,
Ryuji Okazaki2, Hikaru Yabuta6, Kanako Sakamoto7, Shogo Tachibana7,8, Sei-ichiro Watanabe9,
Yuichi Tsuda7 and the Hayabusa2-initial-analysis SOM team
1

JAMSTEC, 2 Kyushu Univ., 3 Hokkaido Univ., 4 Tohoku Univ., 5 Kyoto Univ.,
6
Hiroshima Univ., 7 JAXA, 8 Univ. Tokyo, 9 Nagoya Univ.

The successful collection and recovery of the Ryugu sample [1,2] are leading us to a valuable opportunity for revealing theproperties of the carbonaceous asteroid in the Solar System history; -What is Ryugu? -What are the origins and characteristics
of light elements (C, N, H, O, and S)? -What do their isotopic compositions tell us? -How do they record the primordial chemical
evolution on the asteroid? -How did the interaction of water, organic matter, and minerals affect the evolution and diversity ofindigenous molecules? To answer those important issues by using state-of-the-art small-scale analysis, the SOM (Soluble
Organic Matter) team have been firstly focusing on (i) the initial bulk profiles, especially for the elemental abundance of carbon(C), nitrogen (N), hydrogen (H), oxygen (O), sulfur (S) with the isotopic compositions of δ13C, δ15N, δD, δ18O and δ34S,
respectively, and (ii) the molecular profiles to understand more deeply for nature of indigenous SOM [3-5]. For instance, if
endogenous water-mineral interactions occurred in the asteroid, some aqueous alteration signatures (e.g., process relevant
products including carbonates and other precipitates) should have been recorded to the pristine sample in the bulk and molecularlevels. Assuming the interactions above mentioned, we can trace the potential in-situ temperature of the alteration process byusing clumped isotope surveys of minerals [6]. To assess the objectives, we have been conducting rehearsal analyses foranalytical optimizations and sequential sample processes [3-5, e.g., Figure 1], with a scope of solid and soluble organic aspects[6-9]. In order to deal with samples of unknown identity, especially for bulk nitrogen scale, we validated the dynamic range ofδ15N profiles covered on the basis of pioneering works and compilations for the Inner and Outer Solar System [e.g., 10].

Figure 1 The high precision and high accuracy analytical optimization using reference standards of carbon (C), nitrogen (N),and sulfur (S) for covering wide range isotopic compositions: (a) δ13C, ‰ vs. VPDB; within 13C-enriched and 13C-depleted
profiles, (b) δ15N, ‰ vs. Air; within 15N-enriched and 15N-depleted profiles, (c) δ34S, ‰ vs. VCDT; within 34S-enriched and
34
S-depleted profiles. The x-axis and y-axis stand for the nominal value (= expected) and the measured value (= observed),
respectively. Prior to the Hayabusa2 samples, those analytical validations using the nano-EA/IRMS system [3,4,7] were
performed during the rehearsal analyses (e.g., several carbonaceous chondrite of CM2 and C2-ungrouped: unpublished data)
at JAMSTEC. We have confirmed that there was no memory effect in the analytical lines due to sequential process. For
further of optimization ultra-small-scale sulfur (S) quantification with δ34S validation, please see the latest update [11].





Figure 2 (a, b) Capturing the representative colors during the sequential solvent extraction and the wet chemical treatment
for the Hayabusa2 samples (Ryugu, sample ID: A106 & C107). After solid-liquid separation, the colored supernatant withyellowish and pinkish colors were observed in both A106 and C107, the photo taken in the cleanroom at Dept. Earth Planet
Sci., Kyushu Univ. Since dissolved inorganic elements and organic-inorganic complex molecules also have some kind ofchromaticity depending on the affinity of the solvent, we are in the process of conducting detailed verification. Please see
also the residue of insoluble organic matter (IOM, black color) on the bottom of the vial. The onsite RGB color scale is shown.

We observed some of the colored supernatant during the sequential solvent extraction processes of Ryugu sample (Figure2). These extraction samples have been safely distributed to the SOM team members and are being analyzed in detail at theirlaboratories [12]. The residue of IOM fraction has been also seamlessly transported to the other initial analysis team for further
description [13]. Here, we note that the colors of the extract show the chemical responses of the extractable indigenous organic
molecules to the inherent affinity of the solvent from low to high polarity (i.e., dependent on hydrophilicity, hydrophobicity, andamphiphilicity with both properties). Also, the colored supernatant may indicate that there is a certain amount of components
with a significant absorption spectrum (e.g., chemically various carbon skeleton with N-, S-, O-hetero structures). Regarding themolecular-level analysis, we are currently in the process of combining the pieces of the raw data profiles [12], and we expect
synergistic discussions at this symposium in terms of native organic properties within the history of the Ryugu.

References[1] Tachibana S. et al., #1289, 52nd LPSC (2021); Tachibana S. et al., Geochem. J. 48, 571-587 (2014).
[2] Yada T. et al., #2008, 52nd LPSC (2021).
[3] Naraoka H., Takano Y., Dworkin, J. P. et al., #6314, 82nd Met Soc (2019); Naraoka H. et al., #1362, 51st LPSC (2020).
[4] Ogawa N. O. et al., 51st LPSC (2020); Ogawa N. O. et al. Earth, Life, Isotopes, Kyoto Univ. Press. (2010).
[5] Yoshimura T. et al., #1971, 51st LPSC (2020); Yoshimura, T. et al. J. Chromatogr. A 1531, 157-162 (2018).
[6] Wang Z. et al., Anal. Chem. 92, 2034-2042 (2019); Bonifacie M. et al., Geochim. Cosmochim. Acta 200, 255-279 (2017).
[7] Kebukawa Y. et al., Meteorit Planet Sci. 56, 1311-1327 (2021); Kebukawa Y. et al., Geochim. Cosmochim. Acta 271, 61-77(2020); Chan H. S., et al., Earth, Planets Space, 68, 7 (2016).
[8] Oba Y. et al., Nature Commun. 10, 4413 (2019); Oba Y. et al., Nature Commun. 11, 6243 (2020).
[9] Takano Y. et al., Inter. J. Mass Spectrom. 462, 116529 (2021).
[10] Kerridge J.F. Geochim. Cosmochim. Acta 49, 1707-1714 (1985); Füri, E. and Marty B., Nature Geosci. 8, 515-522 (2015).
[11] Ogawa N. O. et al., #PR0203, Geochem. Soc. Jpn. (2021).
[12] Naraoka H., Takano Y., Dworkin, J. P., this symposium. & the other reports from the Hayabusa2-initial-analysis SOM team.
[13] Initial reports from the Hayabusa2-chemistry, -stone, -sand, -volatile, -IOM team at this symposium.

Compound distribution determined by nanoLC-Orbitrap MS
Francois-Regis Orthous-Daunay1, Cédric Wolters1, Véronique Vuitton1, Roland Thissen1, Junko Isa2, Hiroshi Naraoka3,
Hisayoshi Yurimoto4, Tomoki Nakamura5, Takaaki Noguchi6, Ryuji Okazaki7, Hikaru Yabuta8, Kanako Sakamoto9, Shogo
Tachibana9,10, Seiichiro Watanabe11 and Yuichi Tsuda9 , and the Hayabusa2-initial-analysis SOM team1

Univ. Grenoble Alpes CNRS IPAG, 2Tokyo Inst. Tech., 3Kyushu Univ., 4Hokkaido Univ., 5Tohoku Univ., 6Kyoto Univ., 7NASA
Goddard Space Flight Center, 8Hiroshima Univ., 9JAXA, 10Univ. Tokyo, 11Nagoya Univ

The Hayabusa2 mission is no less than the first opportunity to infirm or confirm theories about the formation of C-type
asteroids [1], [2]. The origin and nature of the organic molecules Ryugu bears will tell which part of this chemistry takes placeon this type of airless bodies and which part in inherited by accretion. The comparison with carbonaceous chondrite will be themethod to evaluate if what has been interpreted from well-studied meteoritical samples is still valid for actual asteroid regolith.
This study focuses on the molecular mixture complexity observed thanks to the combination of two analytical methods: liquid
phase chromatography and high-resolution mass spectrometry [3]. Samples from the first (named A106) and second (C107)
encounter with Ryugu were washed with different solvents in order to extract the soluble organic compounds in a sequence ofincreasing polarity in Kyushu University. Each extract was separated on an amide column with limited volume and flow in a
so-called nano-liquid-chromatography (nano-LC) protocol. The chemical separation is monitored through time by Orbitrapmass-spectrometry (Orbitrap-MS).
This provides three observables for each compound present in the Ryugu soil extract: an intensity evaluating its relative
abundance, a retention time depending on its structure and a molecular weight equivalent to its atomic composition. With
thousands of different compounds, mixtures usually exhibit peculiar patterns in this three-dimensional framework. For instance,
the relative abundance of phospholipids in terrestrial living cells varies by orders of magnitude if the carbon atoms number is
odd or even, making contamination by fingerprints easy to detect. We used the ATTRIBUTOR routines developed at
University of Grenoble Alpes to extract relevant patterns in the Ryugu extracts chromatograms [4].
The most remarkable feature found in both meteorites and Ryugu samples is a ubiquitous polymerization pattern [5]. Almost
each measured mass is part of a network linking it to other molecules with one more carbon atom, two more hydrogen atoms
or any combination of these. A typical bell-shaped intensity distribution indicates that the whole mixtures are likely to be of
one single synthesis origin [6]. Variability of the distribution characteristics goes with a complex origin of subsequent
processes. This type of mass and intensity patterns is difficult to find in other terrestrial natural samples.
The less polar molecules found in Murchison have extremely broad distributions, only matched by some of the Ryugu’s
compounds and other chondrites. For these molecules, the best analogues are solid residues generated out of gas mixtures inplasma chambers [7]. Experimental polymers synthesized in liquid phase or by irradiation of ices have significantly different
polymerization patterns [8].
The chemical structure of compounds found in Ryugu slightly differs from the one in the CM2 Murchison chondrite. As ofpreliminary identification, the less polar compounds are similar between Ryugu and Murchison while the most polar molecules
have significantly different retention times. Assuming polar compounds are more likely to be part of a reaction in liquid water,
the discrepancy between Murchison and Hayabusa2 samples could be due to different degree of aqueous alteration on theirparent bodies.
References[1] Tachibana, S. et al. 2021.Lunar Planet. Sci. Conf.p. 1289 [2] Yada, T. et al. 2021.Lunar Planet. Sci. Conf.p. 2008 [3]Naraoka, H.Takano, Y.Dworkin, J. P.and SOM Analysis Team. 2020.Lunar Planet. Sci. Conf.p. 1362 [4] Orthous-Daunay, F.R.Thissen, R.and Vuitton, V. Apr. 2019.Proc. Int. Astron. Union.vol. 15, no. S350.pp. 193–199 [5] Naraoka, H.Yamashita,
Y.Yamaguchi, M.and Orthous-Daunay, F. R. 2017.ACS Earth Sp. Chem.vol. 1, no. 9.pp. 540–550 [6] Orthous-Daunay, F.-R.
et al. 2019.Geochem. J.vol. 53, no. 1 [7] Bekaert, D. V. et al. 2018.Astrophys. J.vol. 859, no. 2.p. 142 [8] Vinogradoff,
V.Bernard, S. Le Guillou, C.and Remusat, L. 2017.Icarus.vol. 305.pp. 358–370

Highest molecular diversity and structural complexity revealed with ultrahigh resolution
mass spectrometry and nuclear magnetic resonance spectroscopy of Ryugu´s samples
Philippe Schmitt-Kopplin1, 2, Norbert Hertkorn2, Marianna Lucio2, Marco Matzka2, Mourad Harir2,
Philippe Diederich2, Hiroshi Naraoka3, Hisayoshi Yurimoto4, Tomoki Nakamura5, Takaaki Noguchi6,
Ryuji Okazaki3, Hikaru Yabuta7, Kanako Sakamoto8, Shogo Tachibana8,9, Seiichiro Watanabe10 and Yuichi Tsuda8
and the Hayabusa2-initial-analysis SOM team1

Technische Universität Muenchen, Germany, 2 Helmholtz Zentrum Muenchen, Germany,3
Kyushu Univ., Japan, 4Hokkaido Univ., Japan, 5Tohoku Univ., Japan, 6Kyoto Univ., Japan,
7
Hiroshima Univ., Japan, 8JAXA, Japan, 9Univ. Tokyo, Japan, 10Nagoya Univ., Japan.

The surface and possible sub-surface materials of the asteroid Ryugu were recovered during the two touch-down
sampling by the Hayabusa2 spacecraft. Here we present the first results on the solvent soluble organic matter (SOM)
using ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectroscopy (FTICR/MS) complemented
with high field nuclear magnetic resonance spectroscopy (NMR) [1-3]. The two samples A106 (first touchdown) andC107 (second touchdown) were sequentially extracted in the Hayabusa2-initial-analysis SOM team with various polar
and apolar solvent extracts and demonstrate a never seen molecular complexity and diversity.
We confirm herewith the close similarity and the possible comparison of the solvent extracts with meteoritic
material to the Hayabusa2 return samples. We analyzed the sequential hexane, dichloromethane (DCM), methanol
and water extracts with NMR and with electrospray ionization (ESI) and atmospheric pressure photoionization (APPI)[4] FTICR/MS systematically for both negative and positive ions. The hundred thousands of signals were filtered,converted and assigned into more than 24,000 elementary compositions consisting of carbon (C), hydrogen (H),nitrogen (N), oxygen (O) and/or sulfur (S). Organomagnesium compounds (CHOMg, CHOSMg) were not found andthis reflects the low temperature processes on the parent body [5, 6]. As shown for carbonaceous chondrites previously,
our results confirm that the extraterrestrial chemical diversity is much higher compared to terrestrial biological andbiogeochemical spaces and consists in a regular continuum (i) of small to macromolecules (ii) of carbon oxidation
states from apolar (CH, polycyclic aromatic hydrocarbons and branched aliphatics) to polar small molecules (CHO)
with increasing functionalized oxygen and heteroatom contents (CHN, CHS, CHNO, CHOS) leading to the observed
differential solvent type solubility. We revealed specific known molecular targets (CHN+, CHNO+) [4] and show
evidences of multiple chemosynthesis pathways in describing the carbon oxidation state distribution and heteroatom
contributions to the assembly of multiple complex endogen molecules; these also reflect cold hydrothermalism
involved on the parent body [5,6]. We also confirm the high importance of chemical processes involving specificnitrogen and sulfur chemistry [7, 8]. The two fractions analyzed show an extreme coverage in structural features in
APPI and only slight differences in the apolar solvents in ESI. The A106 sample showed slight differences only withhigher mass range and more oxygenated compounds. The C107 sample had increased abundance and uniqueness ofmore unsaturated carbon and low oxygenated compounds that may have disappeared due to surface processing (somehypothesis could be cosmic irradiation at the surface). These samples presents a unique opportunity of having a direct
and low invasive insight into the complex organic diversity present on 162173 Ryugu.

Figure 1. Selected results from the analysis of the solvent extracts of A106 (24159 formula) and C107 (23250 formula) analyzed
with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) in electrospray ionization negative mode (ESI(-))
and atmospheric pressure photoionization (APPI(+)). (A) nominal mass 319 details of dichloromethane (DCM) extracts of the CM2
Aguas Zarcas, A106, C107 and the DCM-blank with the annotated elementary compositions as CH, CHO and CHNO fromultrahigh resolution. (B) counting of the thousands of elementary compositions in the C, H, O, N, S space as obtained from ESI(-)
and APPI(+) and there abundance variations within the different extraction solvents for the A106 and C107 samples. (C)visualization of the structural information retrieved from the elementary compositions as van Krevelen diagram plots describing
the differences in oxygenations between the two ionization modes ESI(-) and APPI(+) and the profiles of the non-oxygenated CH,
CHS and CHN compounds.

References[1] Schmitt-Kopplin, P. et al. 2010. Proc. Natl. Acad. Sci. U.S.A., 107:2763. [2] Ruf, A. et al. 2018. Life 8:18. [3]Hertkorn, N. et al. 2015 Magn. Reson. Chem., 53:754. [4] Herzog J. et al. 2019. Life, 9:48. [5] Ruf. A. et al. 2017 Proc.
Natl. Acad. Sci. U.S.A., 2017, 114:2819. [6] Matzka, M. et al. 2021. Astrophys. J. Lett., 915:L7. [7] Danger, G. et al.
2021. Nat. Commun., 12:1. [8] Danger, G. et al. 2020. Planet. Space Sci., 1:55.