bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of composition, space weathering, and local resurfacing using ASPECT hyperspectral imager of ESA Hera / Milani mission
Authors: Kohout Tomas , Korda David , Penttilä Antti , Rajamäki Leevi , Palamakumbure Lakshika
Published: July 2024

ASPECT is a flexible hyperspectral imager based on tunable Fabry-Perót interference filter (Näsilä and Kohout 2020). It consists of three independent Vis-NIR imaging channels, one single-point SWIR spectrometer, and a dedicated data processing unit (DPU) based on Xiphos Q7 (Table 1). ASPECT is the prime payload of Milani CubeSat carried by ESA Hera mission (Michel et al. 2022, Kohout et al. 2018) to binary asteroid Didymos-Dimorphos and is also considered for RAMSES and Satis missions to asteroid Apophis.Table 1. ASPECT specificationsAspect will conduct global hyperspectral mapping of the target asteroids with a resolution of 1 m/px from 5 km. The spectral domain contains key information on surface composition and maturity. Combined with high spatial resolution lateral variations in surface properties can be mapped. To extract such information from ASPECT observations we developed two machine learning convolutional neural network (CNN) codes (Korda et al. 2023ab, 2024) to extract scientific information from ASPECT observations.The first code quantitatively detects silicate mineral composition (olivine, orthopyroxene, clinopyroxene modal abundances and their Fe, Mg, and Ca content). The second code evaluates space-weathering level based on spectral match score to the spectral type Q (fresh silicate asteroid) or to the type S (space-weathered). The codes were tested on legacy spatially resolved spectra of the asteroid (25143) Itokawa revealing local space-weathering trends in both mineralogy and space weathering indicators (Fig. 1). The apparent correlation between reduction in olivine content with increasing surface maturity is due to higher olivine susceptibility to space weathering-induced damage and related progressive removal of its diagnostic spectral absorption bands relative to these of pyroxenes.Fig. 1. Local variations in surficial space weathering (left) and olivine content (right) on asteroid Itokawa revealed by the machine learning analysis. Spectral data are obtained by NIRS (Near Infrared Spectrometer) instrument on the Hayabusa (JAXA) spacecraft. The space-weathering level is expressed as a match score to spectral S-type with higher values (redder) being more mature.The codes will be applied on hyperspectral observations of Didymos-Dimorphos or Apophis asteroids to produce composition and space-weathering maps, detect fresh impact events, map ejecta extent, or to detect local resurfacing. The web interface to access the codes for online user spectra classification can be found here:https://sirrah.pythonanywhere.com/uploadReferences:Michel et al. 2022 DOI 10.3847/PSJ/ac6f52Näsilä, Kohout 2020 DOI 10.1109/AERO47225.2020.9172437Kohout et al. 2018 DOI 10.1016/j.asr.2017.07.036Korda, Kohout 2024, DOI 10.3847/PSJ/ad2685Korda et al. 2023a DOI 10.1051/0004-6361/202346290Korda et al. 2023b DOI 10.1051/0004-6361/20224388
Planetesimal gravitational collapse in gaseous environment: thermal and dynamic evolution
Authors: Segretain Paul , Méheut Héloïse , Moreira Manuel
Published: July 2024

To address one of the main unknowns in planet formation, the formation of planetesimals from pebble-sized grains, models often invoke a gravitational collapse of pebble clouds to overcome the various barriers to grain growth and propose processes to concentrate particles sufficiently to trigger collapse. At the same time, the geochemical approach constrains the conditions for planetesimal formation and evolution by providing temperatures that should be reached to explain their final composition. In particular, the origin of noble gases in the terrestrial mantle is still debated and might ultimately provide a unique clue on this stage of planet formation. To elucidate the thermal evolution during the gravitational collapse of the pebble cloud, we run numerical simulations of a self-gravitating cloud of particles and gas coupled by gas drag. We aim at determining how the gravitational energy relaxed during the contraction is distributed among the different energy components of the system, and how this constrains the thermal and dynamical planetesimals history. We characterise the conditions required to achieve a temperature rise of up to 1000K. Our results emphasise the key role of the gas during the collapse.
SHAPE: Investigating innate immunity in real microgravity aboard the International Space Station using advanced human bone marrow organoids.
Authors: Sarkar Ryan , Breideband Louise , Pampaloni Francesco
Published: July 2024

In 2025, NASA through their Artemis program aims to send humans beyond Low-Earth Orbit for the first time since 1972. As focus on space exploration shifts from the International Space Station (ISS) to targets farther away, the impact of long-duration space travel on the human body and the ability to withstand these effects are becoming the primary factors precluding further expansion of humanity’s reach into space. The space environment poses numerous unique challenges to astronauts, with typical examples including immune dysfunction and the loss of bone density. Advanced bone marrow organoids comprised of primary human mesenchymal and hematopoietic stem cells were developed to investigate links between those two phenomena in real microgravity aboard the ISS. The unique spatial requirements necessitated development of a novel system, termed Hydrowells, to facilitate the long-term culture and subsequent fixation of many organoids in a small volume, remotely. Validating Hydrowells as a suitable system for 3D in vitro experiments in space allows for future experiments with diverse model systems.The SHAPE project flew over 2,000 organoids to the ISS to investigate innate immunity in vitro in real microgravity. Morphological analysis demonstrated compact organoids with a hematopoietic stem cell niche under earth gravity while space led to looser cell aggregates. The ISS data will be compared to samples cultured in simulated microgravity, centrifuge controls, and earth gravity. Furthermore, MACE-sequencing (Massive Analysis of cDNA Ends) is currently underway to provide insight into the effects of different gravitational conditions on gene expression regarding innate immunity.Technical insight from SHAPE and the Hydrowells facilitates future 3D in vitro experiments in real microgravity with culture systems as diverse as gastruloids. The results from SHAPE will increase understanding of the interplay between innate immunity and bone morphology in space, enabling the mitigation of health risks to astronauts and freeing humanity to explore our galaxy further.
Instrument design and development of the Venus Emissivity Mapper (VEM) for VERITAS and EnVision
Authors: Hagelschuer Till , Pertenais Martin , Walter Ingo , Dern Patrick , del Togno Simone , Saeuberlich Thomas , Pohl Andreas , Rosas Ortiz Yaquelin Miriam , Westerdorff Karsten , Kopp Emanuel , Fitzner Alexander , Wendler Dennis , Ziemke Claas , Rufini Mastropasqua Sergio , Loetzke Horst-Georg , Alemanno Giulia , Vandaele Ann-Carine , Marcqr Emmanuel , Helbert Joern , Peter Gisbert
Published: July 2024

This paper presents the Venus Emissivity Mapper (VEM) onboard NASAs Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy (VERITAS) and ESAs (EnVision) Venus orbiter missions. The VEM instrument, on EnVision called VenSpec-M, is a multispectral push-broom imager for mapping of the Venus surface and its lower atmosphere. By observation through narrow-band atmospheric windows present in the near-infrared spectral region around 1 µm, VEM will provide a global Venus coverage of >70%. The instruments SNR is on the order of 100 and allows for the detection of thermal emissions like surface rock composition, volcanic activity, water abundance and cloud formation.We present the current VEM design and development status. The VEM instrument employs a telecentric optical system, which focuses images taken on the Venus nightside on a multilayered, narrow-band filter array. It splits the signal into 14 spectral bands, ranging from 790 nm to 1510 nm. Each filter band is imaged onto an InGaAs detector with integrated thermoelectric cooler. The optical system including detector and proximity electronics is mounted on top of an electronics box, which includes the instrument controller and power supply. An optically transmissive turn window mechanism is mounted in front of the entrance optics to protect VEM against contamination and during the aerobraking phase. In addition, a two-stage baffle prevents VEM from scattered light.The delivery of the VEM instrument flight models is currently foreseen in 2028 for VERITAS and 2029 for EnVision. First VEM data obtained from Venus are expected in the 2030s.
Unveiling the dynamics and physical property of asteroid systems based on Gaia astrometric data
Authors: Liu Ziyu , Hestroffer Daniel , Desmars Josselin , David Pedro
Published: July 2024

Gaia is a space mission from the European Space Agency (ESA) that was launched in 2013. The mission opens a window to explore the unprecedented high precision astrometric data for a large population of solar system objects. Its latest data release – the Focused Product Release (Gaia FPR) published in October 2023 – contains 66 months of data, for about 160,000 asteroids. By covering a main-belt asteroid’s typical orbital period, it has been shown that the Gaia data alone can provide very precise heliocentric orbits [1]. Thanks to this unprecedented precision, Gaia data is able to reveal the astrometric signature of binary asteroids. This is the case for the recently discovered binary (4337) Arecibo system, analyzed with the Gaia DR3 data [2]; where an astrometric wobble was clearly detected in a time window of several days covering successive transits. In this study, we continue the research on the Arecibo system, taking into account all the Gaia FPR observations. We begin by fitting the heliocentric orbit. These residuals contain the binary signal, which is proportional to the relative orbit with a scaling factor related to the flux ratio and the mass ratio of the components (see [3], [4] for the analytical formula). We then fit the relative orbit to derive the relevant parameters. We obtain an estimate of the component masses, their density ratio, and flux ratio. With an  estimation of the volume, a bulk density of ρ1 ≈ 1.2 and ρ2 ≈ 1.6, for the primary and secondary, is derived. The results are consistent with an ice-rich body in the outer main belt. The high accuracy of Gaia's astrometric solutions enables us, for the first time, to estimate the individual masses and therefore the density of each component of a Small Solar System binary, which generally offer valuable insights into the formation of the Solar System, as well as its collisions and dynamic evolution. Moreover, with the orbital parameters, we are able to predict future mutual events and stellar occultations that will provide additional constraints on the individual density.  [1] Gaia Collaboration, David, P., Mignard, F., et al. 2023, A&A, 680, A37[2] Tanga, P., Pauwels, T., Mignard, F., et al. 2023, A&A, 674, A12[3] Pravec, P. & Scheirich, P. 2012, Planet. Space Sci., 73, 56[4] Lindegren, L. 2022
Probing Venus’ enigmatic evolution with the new Venus Simulation Laboratory at TU Delft
Authors: Steenstra Edgar S.
Published: July 2024

Venus is like Earth in terms of size, density, and composition. However, both bodies evolved so dramatically differently that Venus is characterized by an uninhabitable, run-away greenhouse atmosphere, in marked contrast to Earth's favorable habitable conditions. Understanding the extreme divergence of Venus and Earth’s evolution is of great importance for understanding our early Earth, climate change as well as for studying the habitability of Earth- and Venus-like exoplanets. The key role of Venus in these fields is reflected by at least three major explorative missions scheduled in the next decade by NASA and/or ESA to study Venus in unprecedented detail.    Interpretation of the latter mission results requires an extensive geochemical understanding of Venus and how volatile species, such as CO2, SO2 and H2O, are distributed (Fig. 1). This larger cycle includes surface weathering processes, (recent) volcanism, and chemical reactions within the Venusian clouds. Such models rely heavily on experimental data. However, conducting systematic experiments under corrosive, high pressure-temperature conditions directly relevant to Venus’ surface and lower atmosphere is very challenging.  Thus, many aspects related to the chemistry Venus’ interior, surface and atmosphere remain poorly constrained. This includes the nature and degree of surface weathering by the corrosive atmosphere, the character of (past) volcanism, the origin of particular surface features and reactions within the sulfuric acid clouds.Figure 1: The Venus Simulation Laboratory (VSL) is aimed to experimentally and numerically constrain volatile element fluxes between Venus’ interior, surface and atmosphereTo study the Venus interior, surface and atmosphere in detail, a new lab is therefore being built at the Planetary Exploration Section, Faculty of Aerospace Engineering, TU Delft, using the ERC Starting Grant ‘’VenusVolAtmos’’’. The lab will initially consist of the following;A Thermogravimetric Analysis – Differential Scanning Calorimetry (TGA-DSC) apparatus with which chemical weathering of the Venusian surface can be studied in situ at the conditions directly relevant to Venus’ lowest atmosphere, while using a controlled, corrosive atmosphere.
A piston cylinder press, with which subsurface magmatism on Venus can be simulated up to a depth of 100 km
A gas mixing furnace, with which magma degassing in the earlier history of Venus can be studied.
More funding is currently requested that would be used for purchasing a high-pressure furnace, with which volcanism can be studied under the present-day dense atmosphere and more controlled reaction chambers, to accomdate multiple experiments at a given time. The specific research questions, progress and experimental goals will be presented at the meeting.Acknowledgements: This work is supported by the ERC Starting Grant ‘’VenusVolAtmos’’ awarded to E.S.S.  
Far tail plasma boundaries at Venus from the Solar Orbiter, Parker Solar Probe and BepiColombo flybys
Authors: Edberg Niklas ,   SolO, PSP and BepiC team
Published: July 2024

We present findings from the several flybys made by the Solar Orbiter, BepiColombo, and Parker Solar Probe missions, aimed at investigating the structure and dynamics of Venus' magnetotail. Our study focuses on the interplay between Venus' plasma environment and the solar wind, which shapes the induced magnetosphere. By analyzing magnetic field and plasma density data, we determine the spatial reach and behavior of Venus' magnetotail, and in particulat focus on the time and location of plasma boundary crossings. Notably, we observe significant differences in boundary crossing positions and characteristics across different encounters, underscoring the dynamic nature of Venus' magnetotail. Key observations include identifying boundary crossings such as the bow shock, observed down to approximately 60 Venus radii (6052 km) downstream, and the induced magnetospheric boundary roughly at 100 Venus radii downstream. This insight sheds light on the extent of the induced magnetosphere and allows for the refinement of existing boundary models. Previous models, based on data from Venus Express, were limited to within approximately five Venus radii of the planet; our analysis suggests modifications to better accommodate far-downstream encounters. Additionally, our analysis reveals the influence of solar wind conditions on magnetotail behavior: during Solar Orbiter's third encounter, characterized by extreme solar wind conditions, significant fluctuations in magnetosheath plasma density and magnetic field properties were observed. However, contrary to expectations perhaps, the increased dynamic pressure did not compress the magnetotail; instead, increased EUV flux during this period is suggested to have led to its expansion.
Constraining the formation region of comets.
Authors: Marschall Raphael , Morbidelli Alessandro
Published: July 2024

There is a general consensus that cometesimals formed in an original reservoir, the primordial Kuiper-belt (PKB), between 20-40 au from the Sun (e.g., review by Nesvorny 2018). From there, they were scattered into the current trans-Neptunian region. In particular, the so-called scattered disk acts as the source reservoir for Jupiter family comets, JFCs (e.g., Duncan & Levison 1997). Yet, the current formation region is primarily constrained by the dynamics that lead to the current day structure of the Kuiper-belt.Here, we discuss independent constraints coming from noble gas abundances. We combine the data from the two instruments ROSINA (Balsiger et al. 2007; Rubin et al. 2018) and COSIMA (Kissel et al. 2007; Bardyn et al. 2017) onboard ESA's Rosetta mission to derive the bulk elemental composition of comet 67P. These measurements show that Krypton and Xenon are only slightly depleted compared to the solar composition, while Argon is strongly depleted. For comparison, e.g., CI chondrites are heavily depleted in these three noble gases. This suggests that comets formed further out in the protoplanetary disk at a distinctly different distance than the parent bodies of CI meteorites. It also suggests that comets formed between the Xenon and Argon condensation lines. The Krypton line, which lies between the Xenon and Argon lines, is at about 25 au for a passive disk. We will show our latest protoplanetary disk models and their implications on where the respective temperatures occur in the disk in more detail.
Dynamics and thermal structure of Jupiter’s thermosphere in response to magnetosphere-atmosphere coupling
Authors: Müller-Wodarg Ingo , Iñurrigarro Rodriguez Peio , Moore Luke , Medvedev Alexander , Koskinen Tommi
Published: July 2024

Jupiter’s upper atmosphere (thermosphere/ionosphere) forms the link between its deeper atmosphere and the vast magnetosphere with its current systems, some of which close in the planet’s auroral region. The combination of acceleration and heating have profound influence on the dynamics and temperatures of Jupiter’s upper atmosphere. The ongoing Juno and future JUICE missions as well as Earth based observations provide us with new measurements and questions about the upper atmosphere structure and dynamics. Fundamentally, the aim is to understand this highly coupled upper atmosphere region which is driven to varying degrees by the magnetosphere and by the deeper atmosphere via vertically propagating waves.Exploring such a complex system requires global numerical models. Based on our Saturn Thermosphere Ionosphere Model (STIM) [1, 2, 3], we have developed a Jupiter Thermosphere Ionosphere Model (JTIM) which includes similar features as STIM, a thermosphere model coupled chemically and dynamically to an ionosphere model. The code numerically solves the coupled non-linear Navier Stokes equations of momentum, energy and continuity, including eddy and molecular diffusion of neutral gases and full two-way ion-neutral coupling. The magnetosphere interaction is currently accounted for by mapping a magnetospheric electric field and precipitation pattern into the polar regions and allowing for particle impact ionization in the auroral regions. The thermosphere’s lower boundary is flexible to allow for coupling to the deeper atmosphere via mean background parameters and atmospheric waves.We present first simulations of the model with a focus on the complex thermosphere dynamics and thermal structure. The use of similar models for both Saturn and Jupiter allows for direct comparisons between the planets and difference in underlying physical processes under differing boundary conditions. We also address the question of the well-known upper atmosphere temperature conundrum which is common to all giant planets in our solar system. References:[1] Müller-Wodarg et al. A global circulation model of Saturn’s thermosphere. Icarus, 180, 2006.[2] Müller-Wodarg et al. Magnetosphere-atmosphere coupling at Saturn: 1 – Response of thermosphere and ionosphere to steady state polar forcing. Icarus, 221, 2012.[3] Müller-Wodarg et al. Atmospheric Waves and Their Possible Effect on the Thermal Structure of Saturn's Thermosphere. Geophysical Research Letters, 46, 2019.
The Habitability of Hydrocarbon Words: Titan and Beyond
Authors: Lopes Rosaly , Malaska Michael , Steven Vance , Darcy Meyer-Dombard , Fagents Sarah ,   Titan NAI Team
Published: July 2024

Titan is an ocean world, an icy world, and an organic world. We consider that Titan’s subsurface ocean and ductile ice are the most likely habitable environments on the moon. The ocean may be in contact with an organic-rich ice-rock core, potentially providing redox gradients, heavier elements, and organic building blocks critical for a habitable environment. Titan’s abundant surface organics could be delivered to the aqueous environment through processes such as impact cratering  and potential convective cycles in the ice shell. Our work investigates the pathways for atmospheric organic products to be transported from the surface to the ocean/core and the potential for ocean/deep ice biosignatures and organisms to be transported to the shallow crust or surface for interrogation and discovery. Our overarching  goal is to characterize the habitable environments on Titan and identify their potential biosignatures. We will present a summary of the work conducted by the team to date, which focuses on the following objectives: (i) Determine the pathways for organic materials to be transported (and modified) from the atmosphere to surface and eventually to the subsurface ocean (the most likely habitable environment). (ii) Determine whether the physical and chemical processes in the ocean create stable, habitable environments. (iii) Determine what biosignatures would be produced if the ocean is inhabited. (iv) Determine how biosignatures can be transported from the ocean to the surface and atmosphere and be recognizable at the surface and in the atmosphere. Figure: Titan’s potential geochemical pathways for organic materials to go from atmosphere to surface and ocean, and for extant chemical biosignatures to go up from the potentially habitable ocean to the surface and atmosphere.   Acknowledgments: Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This work was funded by NASA’s Astrobiology Institute grant NNN13D485T.
Towards Turbulence and Wind Shear Models for the Venus Atmosphere
Authors: Lorenz Ralph
Published: July 2024

The design of in-situ missions such as the DAVINCI probe requires quantitative models of turbulence and wind shear in order to assess their effects on the vehicle motion which in turn can influence radio link performance or camera image blur. Some first-principles estimates can be derived from large-scale wind shears and convective fluxes . Experience with the Huygens probe at Titan also showed that the buoyancy frequency gives an informative guide to wind shear :  the large-scale vertical shear at Venus is typically 2-3 m/s/km : the strong stability just below and above the clouds may permit shears up to 10 m/s/km, these values being a little below and above the maximum seen by Huygens. 10 m/s/km is  considered the upper end of 'light turbulence' in terrestrial aviation.  I also present the limited information we have from Pioneer Venus accelerometer measurements, Doppler tracking (Venera, VEGA and Pioneer Venus) and wind measurements (VEGA balloons). For example, in the middle-cloud convective region, a characteristic turbulence amplitude is ~1.5 m/s over a length scale of about 700m, and some  localized shear reaches ~ 20 m/s/km.  A simple 'random-walk' model for the turbulent wind profile appears to describe the Venera data well. I present the model for the low latitudes to be visited by DAVINCI, and discuss considerations for extending the model to high latitude. 
Equilibrium points and stability around Psyche
Authors: Martin Andreza , Winter Othon , Sfair Rafael , Amarante Andre , Machado Rai , Borderes Gabriel , Valvano Giulia
Published: July 2024

The asteroid Psyche is highlighted in the literature for being one of the largest ever observed,located in the main asteroid belt, with a diameter of approximately 232 km. Classified as typeM, it is speculated based on radar observations, that it is an exposed core of a primitive planet,composed mainly of iron-nickel. Although it was initially believed to have a high density,reaching values of 7.6 g/cm3, recent studies indicate lower values. Given such uncertainty, wesought not to use a specific density, but to explore this range of possible densities for Psyche.For each case, we compute the gravitational potential employing the polyhedral method, inwhich the irregular shape of the object is represented using several tetrahedra, maintaining aconstant density. From this potential, we determine the equilibrium points and their linearstabilities, looking for possible changes in behaviour according to the density. Since linearstability influences the time particles can remain close to the equilibrium point, we integrateorbits around Psyche and analyze the number and lifetime of particles that survive and collidewith the asteroid. The concentrated mass method (MASCONS) was employed and we also tookinto account the radiation pressure. This analysis is essential to assist in missions that aim toorbit the asteroid to collect information, such as the Psyche Mission launched by NASA in2023, which stands out for its objective of exploring a metallic object for the first time,unraveling the uncertainties surrounding this asteroid.
A Fast-Developing All-Sky Meteor Surveillance Network in China
Authors: Li Jian-Yang , Wu Xiaoshu , Li Zhenye , Liang Wenjun , Cui Jun , Liu Jifeng
Published: July 2024

Ground-based meteor surveillance network is the most widely used technique to monitor meteors. We report a newly developed optical meteor surveillance network in China, named the Large Automated Network of Remote All-sky Observatories (LANRAO) for Meteor Surveillance. Our goal is to support a comprehensive study of the dynamic meteoroid environment in near-Earth space. The objectives are 1) Providing nearly continuous monitoring of meteors and precisely determining their 3D trajectories; 2) Discovering new meteor streams and identifying their parent bodies, especially those associated with asteroidal objects; 3) Detecting potential unknown long-period comet impactors to Earth; and 4) Studying the evolution of meteor streams and their contribution to the zodiacal cloud. Additionally, the network will support citizen science, public outreach, and education. The system is composed of a network of self-developed, all-sky cameras and an automated data center. With a limiting magnitude of 4.2 for stars, the cameras can take all-sky images at a frequency of up to 30 Hz, and automatically identify meteors and measure the astrometry using the onboard software. The data center combines the measurements and GPS-based time tags from multiple stations to reconstruct the 3D trajectories and velocities of meteors. The brightness of meteors is estimated with relative photometry utilizing star catalogs. The results are visualized in nearly real-time. A testing network was installed in Beijing in 2023 and has since been operated for one year and detected 7253 meteors, including both sporadic and 225 streams. A full-scale network that currently contains 14 stations was deployed in Guangdong Province and Hong Kong and Macau SARs in December 2023, covering an area of over 180,000 km2. It has successfully observed the Geminids and the Quadrantids meteor showers. In the long term, we plan to expand the network to cover whole China, increase the sensitivity, and add multiband imaging and eventually spectroscopic capability. We also plan to combine this optical network with various atmospheric radars and ionospheric radars already constructed in China to expand the area, temporal, and size coverages of meteors.
Wave-driven cloud formation on Venus
Authors: Imamura Takeshi , Maejima Yasumitsu , Sugiyama Ko-ichiro , Peralta Javier , McGouldrick Kevin , Horinouchi Takeshi , Satoh Takehiko
Published: July 2024

Venus is surrounded by sulfuric acid clouds essential to the planet's climate system. The upper part of the cloud is thought to be of photochemical origin, while the lower part is highly variable and will be more affected by atmospheric dynamics causing condensation and evaporation of sulfuric acid. The specific dynamical processes responsible for the variability are poorly understood.Observations at near-infrared window wavelengths have revealed large opacity variations, which mostly occur in the lower part of the cloud layer. A significant feature is the planetary-scale dark cloud propagating with a period of 4.9-5.5 days, discovered through ground-based observations (Crisp et al. 1991). The IR2 camera aboard the Venus orbiter Akatsuki observed this phenomenon in more detail and found that the planetary-scale cloud discontinuity (disruption) that spans in the north-south direction characterizes the propagating structure (Satoh et al. 2017; Peralta et al. 2020). The relatively large amplitude near the equator and the zonal propagation faster than the background atmosphere indicate that the cloud opacity variation is mainly induced by a Kelvin wave. McGouldrick et al. (2021) analyzed this feature using spectroscopic data taken by Venus Express VIRTIS. They suggested that the cloud particle microphysical properties and trace gas densities change across the discontinuity, and the changes occur in the lower cloud region. Peralta et al. (2020) and McGouldrick et al. (2021) argued that a front associated with a nonlinear Kelvin wave could be responsible for the discontinuity.Some Venus GCMs reproduced 5-6 day periodicities in the vertical wind or the thickness of the lower cloud driven by Kelvin waves with a zonal wavenumber of unity (Peralta et al. 2020; Ando et al. 2021). However, the observed sharp discontinuity was not reproduced in the models. The present study proposes mechanisms for the cloud discontinuity from the viewpoint of front generation through hydraulic jump (bore) and associated cloud formation. A simplified dynamical model, in which a Kelvin wave is artificially forced, and a microphysical model are used to reproduce the phenomenon. This study aims to understand the role of the Kelvin wave in the formation of the lower cloud and the conditions necessary for the appearance of the observed sharp discontinuity.
Laboratory experiments on primordial organic degradation at conditions relevant to ocean worlds interiors
Authors: Lévêque Pauline , Bollengier Olivier , Afonso Carlos , Bujoli Bruno , Champallier Rémi , Hertzog Jasmine , Le Menn Erwan , Marrocchi Yves , Queffelec Clémence , Schmitz Isabelle , Slodczyk Aneta , Sotin Christophe
Published: July 2024

Recent interpretations of space observations suggest that the icy moons of Jupiter and Saturn and the dwarf planet Ceres formed by accreting silicates, sulfides, ices and primordial organics. During accretion and differentiation of these icy bodies, the primordial organics reacted with water. We have carried out laboratory experiments at (P,T) conditions relevant to the interiors of icy moons and dwarf planets to investigate the degradation of the organics with water. The goal is to determine the ions that are eventually dissolved in the ocean and the chemical composition and structure of the refractory organics that mix with silicates and sulfides to form the core of these bodies. The primordial organics are analogs made in the Nebulotron. A recent analysis (Lévêque et al., 2024) demonstrated that these organics have elementary and chemical composition close to that of the organic matter found in the Paris meteorite, which is a carbonaceous chondrite, one of less altered CM chondrites. These organic molecules were mixed with water and placed in three different pressuring devices covering a large domain of pressures (up to 2 GPa) and temperatures (at 200°C and 400°C) conditions relevant to the interior of icy bodies.Gas chromatography has been carried out on sealed capsules reacted in internally heated pressure vessel. In situ Raman spectroscopy and in situ XRD have been carry out on samples pressurized in a Diamond Anvil Cell (DAC). Each device provides complementary information on the evolution of the organic matter solid residues and its byproducts. Gas analyzes and in situ Raman demonstrate that N2 and CO2 are released when OM:H2O mixtures are heated up to 200°C, and CH4 appears at 400°C. Organic matter (OM) evolves towards very condensed PAHs. Being denser than the ocean, that should mix with silicates and sulfides to form a refractory core that further evolves as the temperature raises due to the decay of the long-lived radioactive elements. The primordial OM reacts with water to produce ions which may form carbonates, as observed by our XRD analyzes. These experiments provide potential explanations for the presence of N2 and CH4 in Titan’s atmosphere and for the presence of  carbon-rich regions observed at the surface of Ceres, Europa and Ganymede.
Prompt Patterns For PDS4 Information Modeling
Authors: Hughes John , Padams Jordan , Deen Robert , Joyner Ronald
Published: July 2024

Prompt Patterns provide general and reusable solutions to commonly occurring problems within specific contexts while interacting with a Large Language Model (LLM) such as GPT4. A catalog of generic prompt engineering patterns [1] has been published to help users improve LLM results and to promote further research into prompt engineering. Software engineering software patterns are an analog to prompt patterns, providing reusable solutions to common problems in a particular context.The catalog defines six categories of prompt patterns including Input Semantics, Output Customization, Error Identification, Prompt Improvement, Interaction, and Context Control. Prompt patterns from two of the categories, Input Semantics and Output Customization have been applied to problems found in information modeling for the Planetary Data System (PDS).
Oblique Impact Modelling of the Crater Formation and Icy Ejecta of the "Christmas Eve Crater" on Mars. 
Authors: Wojcicka Natalia , Collins Gareth S. , Rangarajan Vidhya G. , Dundas Colin M. , Daubar Ingrid J.
Published: July 2024

On the 24th of December 2021, an impact produced a 150-m-wide crater on Mars (Fig. 1) and excavated subsurface water ice [1, 2]. The crater is located at 35.10°N, 189.82°E in Amazonis Planitia, and is the largest crater observed to have formed since MRO (Mars Reconnaissance Orbiter) began observations in 2006. The crater presents the lowest-latitude observation of subsurface ice exposed by an impact on Mars [12]. The ice is seen in the proximal ejecta,
A Case Study of Classification Comparison of Venusian Data Layers for Geological Mapping
Authors: Garg Shaifali , Woehler Christian
Published: July 2024

This study investigates the geological characteristics of the transition area between Themis Regio and Helen Planitia on Venus, leveraging a multi-layered dataset comprising Magellan Radar data, Magellan Fresnel Reflectivity, Magellan Topography, VIRTIS Surface Radiance and VIRTIS Emissivity. The selection of this region aligns with the standardized area utilized in the tutorials presented at the GMAP Winter School 2024, facilitating comparative analysis with established geological mapping methodologies. The data layers are meticulously stacked and subjected to comprehensive preprocessing procedures to ensure consistency and mitigate inherent challenges associated with Venusian remote sensing datasets, including atmospheric interference and topographical variations. Subsequently, unsupervised clustering techniques are employed to delineate meaningful spatial patterns within the dataset stack. In this investigation, we explore two widely recognized unsupervised clustering methodologies: K-means clustering and Self-Organizing Maps (SOM).Notably, our analysis reveals that the SOM yields a less cluttered cluster map than the k-means algorithm within the Venusian dataset and appears to capture intricate geological features. Furthermore, the SOM yields a geologically reasonable scene segmentation also without the application of dimensionality reduction techniques such as Principal Component Analysis (PCA), suggesting its robustness in handling high-dimensional datasets inherent to planetary remote sensing. Moreover, beyond traditional clustering methodologies, our research is planned to extend towards supervised learning approaches utilizing the outputs of unsupervised clustering for automated feature identification. This hybrid methodology harnesses the strengths of both unsupervised and supervised learning paradigms, offering a comprehensive framework for geological mapping and feature characterization on planetary surfaces. The findings of this study contribute to advancing our understanding of Venusian geology and refining remote sensing methodologies tailored for planetary exploration. The insights garnered from this research are instrumental not only in unraveling the geological complexities of Venus but also in informing future missions and exploration endeavors aimed at unraveling the mysteries of our neighboring planet.
Constraints on paleo hydrological activities on Mars derived from delta formation
Authors: Luo Yaowen
Published: July 2024

Deltas record fluvial and sedimentary activities on the early Mars. Yet, quantitative hydrologic and sedimentary processes related with their formation need further investigation. Here we quantitatively analysed the fluvial and sedimentary process of seven deltas exhibiting diverse morphologies across different Martian locations. Identification of Martian rivers from valleys formed the basis of our analysis, with estimates made for paleo discharge, sediment transport rates, timescales and requisite water for deltas construction. We considered various water supply processes, and classified the seven deltas into three types based on geological contexts of their supplying valleys and water source. We suppose that the delta formation potentially associated with various scenarios, including retreating erosion, groundwater sapping, ice melting, precipitation, impact events and variations in Martian obliquity, unveiling that a warm climate is not a fundamental requirement for the formation. Based on mass balances, the continuous formation timescales of these deltas range from days to thousands of Martian years. Considering the intermittency of water supply and flow dynamics, these timescales can extend to hundreds of millions of years. These findings allow for quantitatively analysing paleo-sedimentary processes that may preserve geological and climatic cues.
Magnitude-phase curves of the Barbarian asteroids (234) Barbara, (236) Honoria, and (980) Anacostia
Authors: Kwiatkowski Tomasz , Mykhailova Sofiia , Podlewska-Gaca Edyta , Kamiński Krzysztof , Ryzhov Oleh , Bosh Josep M.
Published: July 2024

IntroductionBarbarian asteroids are unique because of their wide negative branch of the polarisation phase curves. Their name comes from (234) Barbara for which such behaviour was first observed [1]. They reside in the inner  part of the Main Belt and are mainly of the L taxonomic class. Since magnitude-phase curves are sensitive to the asteroid surface properties, the question arises as to whether Barbarian asteroids' magnitude-phase curves are also anomalous. To answer this, we are carrying out photometric observations of Barbarian asteroids, fitting their phase curves with the [H,G], [H, G12], and [H, G1, G2] phase functions. These parameters are then compared with those of other asteroids in search of deviations. The results for (599) Luisa and (729) Watsonia have been presented in [2]. At the conference, we will show mag-phase curves for another three Barbarians: (234) Barbara, (236) Honoria, and (980) Anacostia.Observations and ReductionPhotometric observations were carried out using several telescopes in different observatories in the Johnson R band. For Honoria, we collected data during its 2012 opposition and for Barbara and Anacostia during the 2022 and 2023 oppositions, respectively. CCD images were reduced in a standard way, including bias, dark subtraction, and flat-field correction. The magnitudes of asteroids and standard stars were obtained with aperture photometry using the Photometry Pipeline package [3]. ResultsFor each asteroid, composite lightcurves from data collected during the opposition were obtained. Synodic periods were derived by a standard Fourier series fit procedure (Fig. 1). The composite lightcurves were used to correct the partial lightcurves (which did not cover all rotation phases) to the same level of maximum brightness. The magnitudes of the maxima of brightness from different nights were then plotted against the phase angle, producing mag-phase curves, which were fitted with three different phase functions (Fig. 2). This allowed us to compare the obtained G1, G2 parameters with similar parameters obtained by [4] for 127 Main Belt asteroids. The final results will be presented at the conference.Fig. 1. Composite lightcurve of (980) AnacostiaFig. 2. Magnitude-phase curve of (980) Anacostia, based on maxima of brightness obtained from the composite lightcurveReferences[1] Cellino, A., et al. (2006) The strange polarimetric behavior of asteroid (234) Barbara, Icarus, 180, 565[2] Mykhailova, S., et al. (2023) What do the phase curves tell us about the Barbarian asteroids. Asteroids, Comets, Meteors Conference, Flagstaff, Arizona. LPI Contribution No. 2851, 2023, id. 2202[3] Mommert, M. (2017) PHOTOMETRYPIPELINE: An automated pipeline for calibrated photometry, Astronomy and Computing, 18, 47[4] Shevchenko, V. G., et al. (2016). Planetary and Space Science, 123,
All coronae are not equal: which ones can be due to a mantle plume ?
Authors: Davaille Anne , Bombled Maelle
Published: July 2024

Coronae are quasi-circular features, usually associated with faulting and volcanism, that have been observed so far only on Venus Surface. They have been proposed to form through a number of processes: mantle plumes, small-scale upwellings or downwellings, delamination, melting, or some combination of these processes. At least 500 coronae have been identified so far, ranging in size from 50 to 2600 km, with a mean diameter of 250 km. The aim of this work is to determine which ones could be due to a mantle plume.We combine new laboratory experiments on the generation of hot thermal plumes in a convecting mantle with already published data, to determine scaling laws on the number, spacing and size of plumes that can be generated in a convecting Venus mantle, as well as the plumes’signatures when they reach the lithosphere (size of impact, hot temperature anomaly). These depend very strongly on the mantle viscosity structure and local or global layering. Our results suggest that mantle plumes coming directly from the bottom of the mantle could be responsible for coronae with diameters in the range 400-1200 km. Smaller coronae would need at least a second level of plume generation at the mantle transition zone or in the lithosphere (for the smallest). Interestingly enough, Artemis coronae seems too large to have been formed as it is today by a mantle plume impact. However, the occurence of plume-induced roll-back subduction could have been sufficient to enlarge the coronae to its present-day size. 
Comets are fragments: Determining the degree of processing during the collisional grinding of the primordial Kuiper-belt.
Authors: Marschall Raphael , Morbidelli Alessandro , Nesvorný David , Bottke William F. , Vokrouhlický David
Published: July 2024

There is a general consensus that cometesimals formed in an original reservoir, the primordial Kuiper-belt (PKB), between 20-40 au from the Sun (e.g., Nesvorný 2018). From there, they were scattered into the current trans-Neptunian region. The so-called scattered disk is the source reservoir for Jupiter family comets, JFCs (e.g., Duncan & Levison 1997). Crucially, the scattering phase of cometesimals must occur as the gas disk dissipates to prevent the damping of the scattered orbits. This is well described by the final phase of planetesimal-driven migration, particularly Neptune’s migration (e.g., Nesvorný et al. 2018). Current planetesimal formation models predict an initial Gaussian size distribution centred around 100 km (e.g., Polak & Klahr 2023). Therefore, the question arises if such an initial size frequency distribution (SFD) of the PKB can reproduce the observational constraints of the current Kuiper-belt. Indeed, we find in Bottke et al. 2023 that the collisional evolution of the PKB based on planetesimal formation models will evolve into a SFD that is consistent with (i) crater SFDs on icy satellites and KBOs and (ii) observed SFDs of populations derived from the PKB (e.g., Jupiter’s Trojans). The craters on icy satellites allow us to infer the SFD of the PKB population scattered onto planet-crossing orbits and those that went to the scattered disk (i.e., source of Centaurs/JFCs).Because comets originate from that same PKB but are then scattered into the Kuiper-belt, they similarly go through the collisional evolution described above. This raises the question of whether the collisional grinding from 100 km cometesimals to the few km sized comets can preserve the primitive properties of comets (i.a., they contain highly volatile species such as CO and have very low densities). Here, we will present recent simulations showing the degree of compaction and heating due to the collisional evolution.