¹Jamie T Williams,¹Boris T Gänsicke,¹Snehalata Sahu,²David J Wilson,³Detlev Koester,¹Andrew M Buchan,⁴Odette Toloza,⁵Yuqi Li,⁵Jay Farihi
Monthly Notices of the Royal Astronomical Society 541, 1377–1389 Link to Article [https://doi.org/10.1093/mnras/staf1034]
¹Department of Physics, University of Warwick, Coventry CV4 7AL, UK
²Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
³Institut für Theoretische Physik und Astrophysik, University of Kiel, 24098 Kiel, Germany
⁴Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso, Chile
⁵Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁶Department of Physics and Astronomy, University College London, London WC1E 6BT, UK

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¹D. Fernandes,^1,2N.G. Rudraswami,^1,2V.P. Singh
Advancesin Space Science 76, 3171-199 Link to Article [https://doi.org/10.1016/j.asr.2025.06.060]
¹National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula, Goa 403004, India
²Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India

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^1,2P. Grèbol-Tomàs et al. (>10)
Geoscience Frontiers (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gsf.2025.102110]
¹Institut de Ciències de l’Espai (ICE-CSIC), C/ Can Magrans, s/n, Cerdanyola del Vallès, Barcelona 08193, Catalonia, Spain
²Insitut d’Estudis Espacials de Catalunya (IEEC), C/ Esteve Tarradas 1, Parc Mediterrani de Tecnologia (PMT) Campus Baix Llobregat -UPC, Castelldefels, Barcelona 08860, Catalonia, Spain

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¹Changhao Ni,¹Hao Zhang
Astronomy & Astrophysics 699, A116 Open Access Link to Article [DOI https://doi.org/10.1051/0004-6361/202553661]
¹School of Earth Sciences, China University of Geosciences, Wuhan, China

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¹Moshammat Mijjum,¹Marissa M. Tremblay
ACS Earth and Space Chemistry 9, 1881-1892 Link to Article [https://doi.org/10.1021/acsearthspacechem.5c00112]
¹Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, United States

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¹Lise Boitard-Crépeau,¹Cecilia Ceccarelli,¹Pierre Beck,¹Lionel Vacher,²Piero Ugliengo
The Astrophysical Journal Letters, 987 L25 Open Access Link to Article [DOI 10.3847/2041-8213/ade5aa]
¹Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
²Dipartimento di Chimica and Nanostructured Interfaces and Surfaces (NIS) Centre, Università degli Studi di Torino, via P. Giuria 7, 10125, Torino, Italy

The origin of the terrestrial water remains debated, as standard solar system formation models suggest that Earth formed from dry grains, inside the snowline of the protosolar nebula (PSN). Here, we revisit this issue through the lens of computational chemistry. While the classically used snowline relies on a single condensation temperature, recent work in quantum chemistry shows that the binding energy (BE) of water on icy grains has a Gaussian distribution, which implies a gradual sublimation of water rather than a sharp transition. We use the computed distribution of BEs to estimate the radial distribution of adsorbed ice on the dust grains across the PSN protoplanetary disk. Our model reproduces the full range of estimated water abundances on Earth and matches the hydration trends observed in chondrite groups at their predicted formation distances. Thus, we suggest that a significant fraction of Earth’s water may have been acquired locally at early stages of the solar system formation, without requiring delivery from beyond the classical snowline.

^1,2Ronghua Pang et al. (>10)
Earth and Planetary Science Letters 669, 119572 Link to Article [https://doi.org/10.1016/j.epsl.2025.119572]
¹Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, 550081 Guiyang, China
²University of Chinese Academy of Sciences, 100049 Beijing, China
Copyright Elsevier

The redox processes and the formation of magnetic anomalies on the lunar surface are hot topics in lunar science research. Magnetite is the only confirmed ferromagnetic and high-valence iron oxide mineral in lunar soil samples, making it a key target for studying these processes. A recent study of Chang’e-5 (CE5) lunar samples found that magnetite was widespread in the high-Ti lunar basalt regolith and was formed by impacts on the lunar surface. It remains to be confirmed whether this type of magnetite is broadly distributed, and its magnetic characteristics require further analysis. We conducted a micro-analysis of impact-sputtered troilite in the CE5 and Chang’e-6 (CE6) lunar samples. Submicron magnetite and associated α-Fe were widespread in the impact-sputtered troilite. The oxygen-bearing volatiles generated or released by the impact may be critical in the formation of magnetite. Further analysis of ferromagnetic materials indicates this magnetite type exhibits magnetic vortices that are weaker than those of α-Fe. Impact-derived magnetite and α-Fe may be potential magnetic minerals responsible for the magnetic anomalies on the lunar surface. Our research confirms that impact-induced redox reactions and their products, such as magnetite, are widely distributed in the lunar basalt regolith, which may be one reason for magnetic anomalies on the lunar surface.

^1,2Elizabeth Bailey,²Myriam Telus,³Phoebe J. Lam,⁴Samuel M. Webb
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70001]
¹Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, California, USA
²Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California, USA
³Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, USA
⁴Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California, USA
Published by arrangement with John Wiley & Sons

Multiple generations of calcite and dolomite precipitated in CM chondrites during ice melting events that led to episodes of liquid water. Models and laboratory analysis have suggested a long-term transition from oxidizing to reducing conditions during aqueous alteration on the CM parent body. We found that synchrotron X-ray absorption near edge spectroscopy (XANES) can detect relative differences in the oxidation state of trace iron within these carbonates. In CM chondrites, previous work interpreted Mn abundance in calcite as an indicator of relatively early or late formation, and dolomite is understood to form relatively late. In the CM1 chondrite Meteorite Hills 01070, XANES maps reveal that Mn-poor calcite contains more oxidized iron relative to Mn-rich calcite. While these measurements of carbonates support increasing iron reduction with progressive aqueous alteration in MET 01070, comparison among different CM chondrites suggests a complex picture of redox evolution. In addition to carbonates, we performed XANES measurements of the phyllosilicate-rich matrix of Allan Hills 83,100. Pre-edge centroid analysis indicates that this CM1/2 has an oxidation state similar to typical CM2 chondrites. While additional measurements are warranted to confirm the full span of redox trends in CM carbonates, our data do not support a correlation between redox state and petrologic type.

^1,2Rachel Y. Sheppard, ³Jessica M. Weber, ⁴Laura E. Rodriguez, ³Cathy Trejo, ⁵Elisabeth M. Hausrath, ³Laura M. Barge
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2025.116769]
¹Planetary Science Institute, Tucson, AZ, USA
²Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS, Orsay, France
³NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
⁴Lunar and Planetary Institute/USRA, Houston, TX, USA
⁵University of Nevada Las Vegas, Las Vegas, NV, USA
Copyright Elsevier

The high mobility of Li allows it to be used as a tracer for groundwater processes, recording past aqueous conditions. On Earth, a relationship has been noted in multiple field sites between clay mineral abundances and elevated Li in bedrock. Observations from the Curiosity MSL mission at Gale crater on Mars showed a high-clay mineral and high-Li area near the Vera Rubin ridge (VRR) and Glen Torridon region, suggesting Li was perhaps substituting into clay minerals as was seen in these terrestrial field settings. However, the process of this substitution has not been examined in the laboratory using non-field samples, especially not with Mars-relevant mineralogy. To investigate this open question in the laboratory using Mars-relevant regolith and clay minerals, we conducted continuous flow packed-bed reactor experiments to test whether clay minerals affect the Li concentration of Mars regolith simulant MGS-1 during aqueous alteration. The mechanism for Li sorption was also investigated by conducting experiments with clays mixed with glass beads and investigating changes in other elements alongside Li via laser-induced breakdown spectroscopy (LIBS). We tested four dioctahedral clay minerals (kaolinite, illite, nontronite, mixed layer illite/smectite) and two trioctahedral clay minerals (talc, saponite) and found that both talc and illite are capable of increasing the amount of Li sorbed compared to MGS-1 simulant when exposed to Li-bearing groundwater. For MGS-1, the glass beads, and the clay minerals (talc, illite) the primary mechanism appears to be Li substitution for Mg, Al, and K, respectively. This has implications for ongoing Mars missions as well as astrobiology, specifically relating to understanding habitability of areas on Mars and identifying aqueous environments for future mission concepts.

¹Siyu Li, ^1,2Yingnan Zhang, ^1,2Ziwei Wang, ^1,2Bing Yang, ^1,2Liping Qin
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2025.08.006]
¹Deep Space Exploration Laboratory/State Key Laboratory of Lithospheric and Environmental Coevolution, University of Science and Technology of China, Hefei 230026, China
²CAS Center for Excellence in Comparative Planetology, Hefei 230026, China
Copyright Elsevier

Space weathering alters the chemical and isotopic compositions of the lunar surface, potentially obscuring insights into the formation and evolution of the Moon and terrestrial planets. The contribution of micrometeorite bombardment to the space weathering process, however, is poorly understood. In this study, the Ni isotopic composition of the Chang’e-5 regolith from different depths of a drilling core was studied to examine both the meteoritic addition and evaporation within the local regolith. The Chang’e-5 lunar drill core samples exhibit significantly elevated Ni abundances and higher δ60Ni values (0.54–1.06 ‰) compared to lunar basalt samples (0.18 ± 0.01 ‰), indicating preferential loss of isotopically light Ni due to impact-induced evaporation of high-Ni-content impactors. Notably, the δ60Ni values decrease significantly with depth, while Ni content remains unchanged, suggesting that continuous micrometeorite bombardment, rather than simple mixing of evaporated impactor material, is responsible for the observed Ni isotopic fractionation. Based on the Ni/Co and the Ni isotopic compositions, we estimate that the primary micrometeorite impactors at the Chang’e-5 site are chondritic, contributing ∼1–2 wt% of the regolith, while ∼10–30 % of the Ni from the impactors was evaporated under near-saturated conditions. This process preferentially enriches the upper regolith in heavier Ni isotopes during more extensive micrometeorite bombardment, supporting continuous space weathering processes in relatively young regolith at the Chang’e-5 landing site. These findings not only highlight the long-term effects of micrometeorite-impact-induced degassing during the space weathering on the lunar surface but also provide new insights into regolith gardening and the progressive surface modification of airless planetary bodies.