^1,2Kong, Seongyoung,¹Singh, Prashant,^1,2Sarkar, Arka,^1,2Viswanathan, Gayatri,³Kolen’ko, Yury V.,²Mudryk, Yaroslav,^2,4Johnson, Duane D.,^1,2Kovnir, Kirill
Chemistry of Materials 36, 1665-1677 Link to Article [DOI 10.1021/acs.chemmater.3c03003]
¹Department of Chemistry, Iowa State University, Ames, 50011, IA, United States
²Ames National Laboratory, U.S. Department of Energy, Ames, 50011, IA, United States
³Nanochemistry Research Group, International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
⁴Department of Materials Science & Engineering, Iowa State University, Ames, 50011, IA, United States

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^1,2,3He, Ye et al. (>10)
Aerospace 11, 114 Open Access Link to Article [DOI 10.3390/aerospace11020114]
¹Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
²Institutes of Earth Science, Chinese Academy of Sciences, Beijing, 100029, China
³College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China

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^1,2Masahiko Sato,^3,4Kosuke Kurosawa,²Sunao Hasegawa,⁵Futoshi Takahashi
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2023JE007864]
¹Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan
²Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
³Department of Human Environmental Science, Kobe University, Kobe, Japan
⁴Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Japan
⁵Department of Earth and Planetary Sciences, Kyushu University, Fukuoka, Japan
Published by arrangement with John Wiley & Sons

Knowledge of the shock remanent magnetization (SRM) property is crucial for interpreting the spatial change in a magnetic anomaly observed over an impact crater. This study conducted two series of impact-induced SRM acquisition experiments by varying the applied field intensity (0–400 μT) and impact conditions. Systematic remanence measurements of cube-shaped subsamples cut from shocked basalt containing single-domain titanomagnetite were conducted to investigate the effects of changes in pressure and temperature on the SRM acquisition. The peak pressure and temperature distributions in the shocked samples were estimated using shock-physics modeling. SRM intensity was proportional to the applied field intensity of up to 400 μT. SRM intensity data for peak pressure and temperature of up to 8.0 GPa and 530 K, respectively, clearly show that it increases with increasing pressure and decreases with increasing temperature. The SRM has unblocking temperature components up to a Curie temperature of 510 K, and it easily demagnetizes with alternating field demagnetization. The observed SRM properties can be explained by the pressure-induced microcoercivity reduction and temperature-induced modification of the blocking curve. Although the remanence acquisition efficiency of the SRM is significantly lower than that of the thermoremanent magnetization (TRM), the magnetic anomaly originating from the SRM distribution in a broader region may show a contribution comparable to that of the impact-induced TRM distribution in a narrow region.

¹Evgeny Smirnov
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2024.116058]
¹Evgeny SmirnovBelgrade Astronomical Observatory, Volgina 7, 11060, Belgrade, Serbia
Copyright Elsevier

This study explores how well various machine learning classifiers can identify mean-motion resonances in the main belt using supervised learning. The most popular classifiers are assessed: k-Nearest Neighbours, Decision Tree, Gradient Boosting, AdaBoost, Random Forest, and Naïve Bayes. In contrast to previous studies that often relied on default ML configurations, this research conducts a detailed investigation, fine-tuning, and testing of each classifier across various parameters. The results show that simpler models, especially k-Nearest Neighbours and Decision Tree, perform better than more complex ones, particularly in terms of
scores. The paper provides guides on selecting features, parameters, and training set sizes for optimal classifier performance and outlines a method for developing effective machine-learning models for asteroid classification.

¹Clara Maurel,¹Jérôme Gattacceca
Proceedings of the National Academy of Science of America (PNAS) 121, e2312802121 Link to Article [https://doi.org/10.1073/pnas.23128021]
¹CNRS, Aix Marseille Université, IRD, INRAE, Centre de Recherche et d’Enseignement des Géosciences de l’Environnement (CEREGE), Aix-en-Provence 13545, France

Magnetic fields in protoplanetary disks are thought to play a prominent role in the formation of planetary bodies. Acting upon turbulence and angular momentum transport, they may influence the motion of solids and accretion onto the central star. By searching for the record of the solar nebula field preserved in meteorites, we aim to characterize the strength of a disk field with a spatial and temporal resolution far superior to observations of extrasolar disks. Here, we present a rock magnetic and paleomagnetic study of the andesite meteorite Erg Chech 002 (EC002). This meteorite contains submicron iron grains, expected to be very reliable magnetic recorders, and carries a stable, high-coercivity magnetization. After ruling out potential sources of magnetic contamination, we show that EC002 most likely carries an ancient thermoremanent magnetization acquired upon cooling on its parent body. Using the U-corrected Pb-Pb age of the meteorite’s pyroxene as a proxy for the timing of magnetization acquisition, we estimate that EC002 recorded a field of 60 ± 18 µT at a distance of ~2 to 3 astronomical units, 2.0 ± 0.3 My after the formation of calcium-aluminum-rich inclusions. This record can only be explained if EC002 was magnetized by the field prevalent in the solar nebula. This makes EC002’s record, particularly well resolved in time and space, one of the two earliest records of the solar nebula field. Such a field intensity is consistent with stellar accretion rates observed in extrasolar protoplanetary disks.

^1,2,3Fan Liu,^3,4,5,6,7,8Yuan-Sen Ting,^3,4David Yong,^9,10Bertram Bitsch,^1,3Amanda Karakas,²Michael T. Murphy,^11,12Meridith Joyce,¹³Aaron Dotter,^14,15Fei Dai
Nature 627, 501-504 Link to Article [DOI https://doi.org/10.1038/s41586-024-07091-y]
¹School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia
²Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria, Australia
³ARC Centre for All Sky Astrophysics in 3D (ASTRO-3D), Canberra, Australian Capital Territory, Australia
⁴Research School of Astronomy and Astrophysics, Australian National University, Weston, Australian Capital Territory, Australia
⁵School of Computing, Australian National University, Acton, Australian Capital Territory, Australia
⁶Department of Astronomy, The Ohio State University, Columbus, OH, USA
⁷Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, OH, USA
⁸Observatories of the Carnegie Institution of Washington, Pasadena, CA, USA
⁹Max-Planck-Institut für Astronomie, Heidelberg, Germany
¹⁰Department of Physics, University College Cork, Cork, Ireland
¹¹HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Observatory, Budapest, Hungary
¹²CSFK, MTA Centre of Excellence, Budapest, Hungary
¹³Department of Physics and Astronomy, Dartmouth College, Hanover, NH, USA
¹⁴Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
¹⁵Department of Astronomy, California Institute of Technology, Pasadena, CA, USA

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^1,2Qadri S.B.,²Goswami R.,²Imler G.,²Qadri S.N.
Materialia 33, 102035 Link to Article [DOI 10.1016/j.mtla.2024.102035]
¹Retired Emeritus, US Naval Research Laboratory, Washington, 20375, DC, United States
²Materials Science and Technology Division, US Naval Research Laboratory, Washington, 20375, DC, United States

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¹Agrosì, Giovanna, ²Manzari, Paola,¹Mele, Daniela,¹Tempesta, Gioacchino, ¹Rizzo, Floriana,³Catelani, Tiziano,⁴Bindi, Luca
Communications Earth and Environment 5, 67 Open Access Link to Article [DOI 10.1038/s43247-024-01233-w]
¹Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari Aldo Moro, Via Orabona 4, Bari, I-70125, Italy
²Agenzia Spaziale Italiana, Centro Spaziale di Matera, Matera, Terlecchia, I-75100, Italy
³Centro Servizi MEMA, Università di Firenze, Via Capponi 3r, Florence, I-50121, Italy
⁴Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, Florence, I-50121, Italy

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^1,2Chang Nie,^3,4Jin-Ting Kang,¹Yun Jiang,³Si-Jie Wang,^3,4Fang Huang,^1,2,4Wei-Biao Hsu
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2024.03.009]
¹Center for Excellence in Comparative Planetology, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China
²School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, China
³CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
⁴Deep Space Exploration Laboratory, University of Science and Technology of China, Hefei 230026, China
Copyright Elsevier

Stable strontium and barium isotopes are potential tracers for understanding planetary differentiation and the nature of the building blocks of terrestrial planets. Strontium and barium are fluid-mobile elements, but it remains unclear how terrestrial weathering affects the Sr-Ba isotopes compositions in achondrites, thus hampering the utility of Sr-Ba isotopes in cosmochemistry. In this study, we conducted acetic acid leaching on three eucrites with varying weathering degrees (fall: Qiquanhu, hot desert find: Northwest Africa (NWA) 13583, and Antarctic find: Grove Mountains (GRV) 13001). Combined with detailed petrography observations and major and trace element analyses, we investigated the variations in Sr-Ba isotopes during terrestrial weathering. The degree of weathering follows an order of: NWA 13583 > GRV 13001 > Qiquanhu, evaluated based on several alteration signs, including: the presence of secondary carbonate, the enrichment of large ion lithophile elements (e.g., Sr, Ba, and U), and the Ce and Eu anomalies. The concentrations of Sr and Ba in the leachates of NWA 13583 show a good correlation with Ca, suggesting that the soluble Sr and Ba are derived from secondary carbonate. Differently, the concentrations of Sr and Ba in the leachates of Qiquanhu correlate with Al and Na, suggesting that the soluble Sr and Ba in Qiquanhu are derived from primary plagioclases. This also indicates that silicates dissolution may be inevitable in an acid leaching experiment for achondrites, even when using weak acetic acid. GRV 13001 shows no variation in Sr and Ba isotopes during leaching experiments. The δ138/134Ba in the leachate (0.26 ± 0.02 ‰) of Qiquanhu is higher than that of the residue (0.04 ± 0.03 ‰), reflecting that aqueous fluids preferentially uptake heavy Ba isotopes during plagioclase dissolution. Conversely, the leachate of NWA 13583 shows lower δ138/134Ba (-0.19 ± 0.05 ‰) than that of residue (-0.10 ± 0.03 ‰), reflecting the lighter Ba isotope composition in carbonate. Notably, the residue of NWA 13583 has δ138/134Ba ∼ 0.1 ‰ lower than those of Qiquanhu and GRV 13001. This discrepancy may reflect plagioclase dissolution during hot-desert weathering rather than magmatism on the parent body. Different from Ba isotopes, the δ88/86Sr of Qiquanhu shows no variation in the leaching experiment, suggesting that the dissolution of plagioclase causes no Sr isotope fractionation. For NWA 13583, the δ88/86Sr of leachate is slightly heavier than that of leaching residue and bulk rock, reflecting high δ88/86Sr in terrestrial fluids. Our results suggest that Ba and Sr isotopes of eucrites show different behaviors during terrestrial weathering. Sr isotopes show a smaller fractionation scale and may have greater resistance for terrestrial weathering than Ba isotopes.

¹Tai-Jan Huang,¹Eshan Ganju,¹Hamid Torbatisarraf,²Michelle S. Thompson,¹Nikhilesh Chawla
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14157]
¹School of Materials Engineering, Purdue University, West Lafayette, Indiana, USA
²Department of Earth, Atmospheric, and Planetary Science, Purdue University, West Lafayette, Indiana, USA
Published by arrangement with John Wiley & Sons

The microstructural characterization of lunar agglutinate samples serves many essential purposes in lunar science and cosmochemistry, from understanding the formation process of lunar regolith to preparing for human activity on the Moon. In this study, an advanced correlative characterization methodology was employed to examine the microstructure of a lunar agglutinate particle retrieved from the Apollo 11 mission. The multimodal characterization efforts were centered around 3-D x-ray computed tomography (XCT) and were complemented by 2-D techniques, including scanning electron microscopy and energy-dispersive x-ray spectroscopy. The nondestructive nature of the XCT allowed us to preserve the lunar dust particles, while its 3-D nature allowed us to extract meaningful microstructural information inaccessible via traditional 2-D characterization techniques. The multimodal correlative analysis further allowed us to identify the compositional and microstructural features of the agglutinate. These observations were linked to the formation process of the agglutinate to inform a hypothesis on the dynamic formation sequence of lunar regolith.