¹Pengfei Zhang (>10)
Journal of Geophysical Research: Planets (in Press) Link to Article [DOI: 10.1029/2026JE009859]
¹Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
Published by arrangement with John Wiley & Sons

China plans to return samples from the near-Earth asteroid (469219) Kamoʻoalewa, which we previously identified as an LL-chondrite-compositional, highly space-weathered object with fine-grained regolith. In this study, we developed 10 mL of Kamoʻoalewa regolith simulant, designated “IGCAS-AST01,” by irradiating LL5/6 chondrite (Kheneg Ljouâd) powder with a high-energy pulsed laser. We then analyzed the composition, grain size distribution, density, porosity, visible to near-infrared reflectance spectrum, emission spectrum (approximated as 1–Reflectance), thermal diffusivity, specific heat capacity, and microstructural features of both the fresh (unirradiated) powder and IGCAS-AST01. IGCAS-AST01 is composed of 57.8 vol.% olivine, 19.9 vol.% orthopyroxene, 5.6 vol.% diopside, 12.2 vol.% plagioclase, 2.6 vol.% troilite, and minor amounts of other phases. It has a mean size of 26.99 μm, a median size of 23.19 μm, a density of 1196.8 kg m⁻³, and a porosity of 64.3%. Additionally, IGCAS-AST01 exhibits a low reflectance of 0.1 at 0.55 μm and an extremely steep spectral slope. In the temperature range of 253.15–473.15 K, its thermal diffusivity and specific heat capacity range from 3.6–4.7 × 10⁻⁶  m² s⁻¹ and 718.43–890.20 J kg⁻¹ K⁻¹, respectively. Furthermore, thick amorphous rims and abundant nanophase metallic iron particles are observed in olivine and pyroxene grains of IGCAS-AST01. These results could support the Tianwen-2 mission’s payload calibration, sampling operations, on-orbit scientific data interpretation, and future sample analysis.

^1,2M. Kołodziej, ³B. Pieterek, ⁴G. Zieliński, ¹K. Załęski, ¹E. Coy
Journal of Geophysical Research: Planets (in Press) Open Source Link to Article [DOI: 10.1029/2026JE009937]
¹NanoBioMedical Centre, Adam Mickiewicz University in Poznan, Poznan, Poland
²Institute of Molecular Physics, Polish Academy of Sciences, Poznan, Poland
³Geohazard Research Unit, Institute of Geology, Adam Mickiewicz University in Poznan, Poznan, Poland
⁴Micro-area Analysis Laboratory, Polish Geological Institute—National Research Institute, Warsaw, Poland
Published by arrangement with John Wiley & Sons

Meteorites serve as an exceptional source of insight into our planet and the Solar System. Most meteorite fragments were recovered hundreds to thousands of years after their fall, and therefore exhibit varying degrees of terrestrial weathering, which has altered or completely removed weather-sensitive mineral phases. This study focuses on two aubrites—NWA 14582 and Ribbeck—examining the differences in their mineral composition. The NWA 14582 was collected in a desert long after its fall and has undergone significantly greater shock metamorphic alteration than the Ribbeck meteorite. The alterations are evidenced by the structural changes in its enstatite and diopside, along with the absence of feldspars, which have transformed into maskelynite. The Ribbeck meteorite, recovered shortly after its descent, revealed several mineral phases not present in NWA 14582. Electron microprobe investigations confirmed that minerals such as troilite, daubréelite, schreibersite, and kamacite exhibit resistance to weathering. Conversely, the observed minerals, such as heideite, caswellsilverite, oldhamite, pentlandite, and alabandite, appear to be particularly susceptible to terrestrial weathering processes. Our observations further indicate that the climate at the fall site can have a substantial impact on the preservation of primary mineral phases and the formation of secondary weathering products. We additionally report a Cu-based iodide in an early sample preparation that was not preserved in subsequently prepared mounts, as well as a rare Al–Cu–Zn alloy in Ribbeck. Further microchemical and isotopic analyses are required to determine the provenance of these phases.

¹Zhichen Zhao (>10)
Journal of Geophysical Research: Planets (in Press), Link to Article [DOI: 10.1029/2026JE009684]
¹MOE Key Laboratory of Advanced Micro‐Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai, China
Published by arrangement with John Wiley & Sons

Nanophase iron (np-Fe0$$), as one of the key products of space weathering, is widely observed in the near-surface layer of lunar materials, providing crucial evidence for their geological evolution. Here we report the discovery of np-Fe0$$ with a rare lamellar morphology, embedded in Fe-Ti-Cr oxide solid solutions within the interior of the lunar meteorite NWA 4734, characterized by nanometer-scale thicknesses and micrometer-scale lateral dimensions. Notably, these lamellae exhibit a unique three-layer core-shell structure, consisting of np-Fe0$$ core, Fe3+$$-bearing shell, and ilmenite-dominated outer layer. This finding offers new insights into the formation process of np-Fe0$$ in lunar materials through thermal decomposition and disproportionation associated with impact events and space weathering, and reveals a novel pathway for nanomaterial synthesis under extreme conditions.

^1,2N. Imae
Journal of Geophysical Research: Planets, 131, e2026JE009763 Open Access Link to Article [DOI: 10.1029/2026JE009763]
¹National Institute of Polar Research (NIPR), Tokyo, Japan
²The Graduate University for Advanced Studies (SOKEDAI), Tokyo, Japan
Published by arrangement with John Wiley & Sons

Enstatite chondrites record highly reducing conditions in the early solar nebula, yet the origin of their abundant sulfides remains unclear. Niningerite (MgS) and oldhamite (CaS) are ubiquitous in EH3 enstatite chondrites and distinguish them from other chondrite groups. To investigate sulfide formation, we conducted sulfidation experiments under ultra-reducing conditions using evacuated silica-glass tubes to reproduce extremely low oxygen pressure environments. Experiments at 1,200–1,420°C and IW−5 to −6 with pyrrhotite–troilite buffers examined reactions of Mg- and Ca-bearing silicates with sulfur-rich gas. Niningerite formed from forsterite–enstatite, and oldhamite from diopside, producing granular niningerite surrounding olivine and enstatite and granular oldhamite associated with diopside, coexisting with cristobalite and enstatite. Mg–Fe compositions of synthetic niningerite are included in those in EH3 chondrites. In the experiments, niningerite and oldhamite did not form within the coexisting Fe-S reservoir, whereas natural EH3 meteorites show enrichment of these sulfides in metal-sulfide nodules, a key discrepancy with natural EH3 textures. This suggests that the precursors of chondrules and metal nodules—aggregates of chondrules and metal nodules—underwent melting and segregation events, during which niningerite and oldhamite preferentially partitioned into the metal nodules. These multi-stage high-temperature processes provide new constraints on the physicochemical environment of sulfide formation in the inner solar nebula.

¹M. C. Rojas, ¹M. Mantegazza, ²J. L. Bishop, ¹M. G. Spagnuolo
The Planetary Science Journal, 7, 130 Open Source Link to Article [DOI: 10.3847/PSJ/ae5dcb]
¹IDEAN-UBA CONICET Instituto De Estudios Andinos “Don Pablo Groeber,” Argentina
²SETI Institute and NASA Ames Research Center, Mountain View, CA 94043, USA

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

^1,2Victoria Muñoz-Iglesias, ³Elodie Gloesener, ⁴Carolina Gil-Lozano, ⁵Mathieu Choukroun, ¹Olga Prieto-Ballesteros, ¹Oscar Ercilla Herrero, ¹Maite Fernández Sampedro, ⁶Valentín García Baonza, ²Gabriel Tobie
The Planetary Science Journal, 7, 106 Open Access Link to Article [DOI: 10.3847/PSJ/ae63c1]
¹Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir km 4, 28850 Torrejón de Ardoz, Madrid, Spain
²Nantes Université, Univ Angers, Le Mans Université, CNRS, Laboratoire de Planétologie et Géosciences, LPG, UMR 6112, France
³Univ. Lille, CNRS, UMR 8523—PhLAM—Physique des Lasers Atomes et Molécules, F-59000 Lille, France
⁴Centro de Investigación Mariñas, XM1, Universidade de Vigo, Vigo, Spain
⁵Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
⁶Malta-Consolider Team and Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Plz. Ciencias 2, E-28040 Madrid, Spain

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

¹Radek Novotný, ^1,2Gunther Kletetschka, ³Filip Košek, ⁴Daniela Popelková
Icarus (in Press) Open Source Link to Article [DOI: 10.1016/j.icarus.2026.117299]
¹Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Faculty of Science, Charles University, Prague, Czech Republic
²Geophysical Institute, University of Alaska Fairbanks, United States of America
³Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Prague, Czech Republic
⁴Imaging Methods Laboratory, BIOCEV, Vestec, Czech republic
Copyright Elsevier

This study investigates the response of lunar breccia minerals and selected reference materials to accelerated Ga⁺ ion irradiation using focused ion beam (FIB) processing combined with Raman spectroscopy. Anorthite and pyroxene bearing clasts from Apollo 15 breccias 15405 and 15445 were examined alongside monocrystalline silicon, magnetite, and pyrite to evaluate mineral specific structural modifications induced by heavy ion exposure. Samples were characterized by Raman spectroscopy before and after irradiation with 30 keV Ga⁺ ions at four beam currents (0.43, 0.79, 2.5, and 9.3 nA). Silicate phases exhibited band broadening, peak shifts, and partial amorphization consistent with increasing lattice disorder. Monocrystalline silicon showed progressive damage of the crystalline structure, while magnetite and pyrite displayed enhanced structural disorder and modifications of Fe-bearing spectral features. At the highest irradiation conditions, Ga implantation and local heating may have contributed to the observed changes. Based on published SRIM-derived displacement estimates, the maximum Ga⁺ fluence applied in this study corresponds to approximately 10⁵–10⁶ years of natural solar wind exposure in terms of cumulative atomic displacement damage. This estimate is intended only as an approximate comparison between laboratory irradiation and natural space weathering. Although Ga⁺ FIB irradiation does not directly reproduce natural solar wind conditions, it provides an accelerated approach for assessing the relative susceptibility of planetary materials to heavy ion induced structural degradation and offers implications for future spectroscopic and paleomagnetic investigations of lunar samples.

^1,2Peter Jenniskens, ¹Stuart Pilorz, ²Darrel Robertson, ^2,3Eric C. Stern
Meteoritics & Planetary Science (in Press) Open Source Link to Article [DOI: 10.1111/maps.70203]
¹SETI Institute, Mountain View, California, USA
²Asteroid Threat Assessment Project, NASA Ames Research Center, Moffett Field, California, USA
³Hyperspace Technologies, Inc., Mountain View, California, USA
Published by arrangement with John Wiley & Sons

How does the energy deposition profile (light curve), deceleration, and penetration depth in Earth’s atmosphere depend on asteroid composition and meteorite type? Here, we present the light curve and velocity profile of 75 bolides from camera-documented meteorite falls. The light curves as a function of altitude generally develop in the following seven phases: Phase (1) an initial rapid brightening; (2) a gradual increase that sometimes shows periodic brightness variations; (3) an onset and rapid increase of brightness until reaching a plateau; (4) a plateau with occasionally chirping brightness oscillations; (5) flares that result in fragments in the meteor wake; (6) an end flare of sometimes different color; and (7) ongoing ablation and fragmentation until dark flight. These seven phases are interpreted as resulting from solid bodies that cause early brightness oscillations from meteoroid spin, a plateau because of melting and reaching melting equilibrium, chirping oscillations due to plasma instabilities, flares due to fragmentations along fractures from dynamic pressure and thermal stress, and an end flare when the surviving back of the meteoroid explodes. This paper discusses the systematics of how the phase heights depend on entry speed, entry angle, initial mass, and meteorite type. The dynamic pressures during the onset of fragmentation and the end flare correlate with the tensile strength of the recovered meteorites. The results have implications for Planetary Defense when anticipating the energy deposition curve of small solid-body airbursting asteroid impacts like Chelyabinsk.

¹Adrien Saurety, ^1,2Razvan Caracas
The Planetary Science Journal, 7, 63 Open Source Link to Article [DOI: 10.3847/PSJ/ae4488]
¹Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris, 75005, France
²The Center for Planetary Habitability (PHAB), University of Oslo, Oslo, 0371, Norway

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

¹Ziyu Huang, ¹Masatoshi Hirabayashi
The Planetary Science Journal, 7, 62 Open Source Link to Article [DOI: 10.3847/PSJ/ae4504]
¹Georgia Institute of Technology, Atlanta, GA 30332, USA

We currently do not have a copyright agreement with this publisher and cannot display the abstract here