¹Charles E. Woodward,²Dominique Bockélee-Morvan,³David E. Harker,⁴Michael S. P. Kelley,^5,6Nathan X. Roth,⁷Diane H. Wooden,⁸Stefanie N. Milam
The Planetary Science Journal 6, 139 Open Access Link to Article [DOI 10.3847/PSJ/add1d5]
¹Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455, USA
²Observatoire de Paris, France
³Department of Astronomy and Astrophysics, University of California, San Diego, 9500 Gilman Drive, MC 0424, La Jolla, CA 92093-0424, USA
⁴University of Maryland, Department of Astronomy, 4254 Stadium Drive, College Park, MD 20742-2421, USA
⁵Solar System Exploration Division, Astrochemistry Laboratory Code 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
⁶Department of Physics, American University, 4400 Massachusetts Avenue NW, Washington, DC 20016, USA
⁷NASA Ames Research Center, SpaceScience Division, MS 245-1, Moffett Field, CA 94035-1000, USA
⁸NASA Goddard Space Flight Center, USA

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¹William F. Bottke,²Alex J. Meyer,³David Vokrouhlický,¹David Nesvorný,⁴Edward B. Bierhaus,⁵Daniella N. DellaGiustina,¹Rachael Hoover,⁶Harold C. Connolly,⁵Dante S. Lauretta
The Planetary Science Journal 6, 150 Open Access Link to Article [DOI 10.3847/PSJ/add46a]
¹Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA
²University of Colorado Boulder, 3775 Discovery Dr., Boulder, CO 80309, USA
³Institute of Astronomy, Charles University, V Holešovičkách 2, CZ-18000, Prague 8, Czech Republic
⁴Lockheed Martin Space, Littleton, CO 80127, USA
⁵Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
⁶Department of Geology, Rowan University, Glassboro, NJ 08028, USA

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^1,2Fridolin Spitzer,^1,3Timo Hopp,^1,2Christoph Burkhardt,³Nicolas Dauphas,^1,2Thorsten Kleine
Earth and Planetary Science Letters 667, 119530 Open Access Link to Article [https://doi.org/10.1016/j.epsl.2025.119530]
¹Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3 37077, Göttingen, Germany
²Institut für Planetologie, University of Münster, Wilhelm-Klemm-Str. 10 48149, Münster, Germany
³Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, Chicago 60637, USA
Copyright Elsevier

Differentiated meteorites sample planetesimals formed earlier than the parent bodies of chondritic meteorites. To evaluate whether these two generations of planetesimals formed from the same or distinct materials, we have analyzed the Fe and Ni isotopic compositions for a large set of differentiated meteorites, representing approximately 26 distinct parent bodies. Most of these samples are genetically related to the carbonaceous chondrite (CC)-type reservoir, which is thought to represent some portion of the outer disk. The new data reveal that early and late CC planetesimals cover a similar range of Fe and Ni isotopic compositions, indicating that all these bodies accreted from the same mixture of dust components, either in a long-lived pressure structure of the disk or in different substructures containing the same materials. Many differentiated meteorites have an isotopic composition similar to the late-formed CR chondrites, indicating that the CR chondrite reservoir was established early and remained isolated for essentially the entire disk lifetime. Finally, CI chondrites are the only CC chondrites whose isotopic composition is not represented among differentiated meteorites. Thus, planetesimals with CI chondrite-like isotopic compositions represent a late burst of planetesimal formation and possibly formed by a distinct mechanism and/ or in a different location from the other CC planetesimals.

¹Jamaledin Baniamerian,¹Sebastian E. Lauro,¹Barbara Cosciotti,¹Alessandro Brin,²Carlo Lefevre,¹Elisabetta Mattei,¹Elena Pettinelli
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008545]
¹Dipartimento di Matematica e Fisica, Università degli studi Roma Tre, Rome, Italy
²Istituto di Astrofisica e Planetologia Spaziali di Roma, (INAF/IAPS), Rome, Italy
Published by arrangement with John Wiley & Sons

Radar sounder investigations of Venus’ crust are particularly challenging, due to the expected high loss character of the rocks at temperatures of hundreds of degrees. The dielectric behavior of hot planetary analogues is poorly understood, as the procedure to measure such samples is difficult, especially in the frequency range of 1–100 MHz typical of planetary radar sounders. In this paper a new experimental setup capable of measuring the complex dielectric permittivity of rock slices at temperatures as high as
C, in a large frequency range is presented. The measurements are based on the open-ended coaxial transmission line approach, where the sample is kept inside an oven to reach thermal equilibrium, and the probe tip is placed in contact with the rock and rapidly removed to limit heat propagation along the probe. The dielectric quantities (real part of permittivity and loss tangent) are computed by inverting the scattering parameters measured with a Vector Network Analyzer. Experimental data are compared with electromagnetic simulations, to define the probe characteristics and its criticalities. To assess the reliability of the setup, the results are validated using Macor ceramic samples for which dielectric properties have been measured and certified at different temperatures and frequencies. The methodology is then applied to a basaltic rock sample to demonstrate its applicability to potential Venusian analogues. The proposed technique instills confidence in the possibility of exploring the complex permittivity parameter space of many igneous and sedimentary rocks at high temperatures.

^1,2,3Qi Sun,^4,5Yu-Yan Sara Zhao,^6,7Kesong Ni,^6,7Zonghao Wang,⁸Wen Yu,⁹Wenqi Luo,⁹Wenbin Yu,⁹Xin Nie,⁹Zonghua Qin,^9,2,5Quan Wan
Journal of Geophysical Research (Planets) Link to Article [https://doi.org/10.1029/2025JE009023]
¹State Key Laboratory of Critical Mineral Research and Exploration, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
²University of Chinese Academy of Sciences, Beijing, China
³School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, China
⁴Research Center for Planetary Science, College of Earth and Planetary Sciences, Chengdu University of Technology, Chengdu, China
⁵CAS Center for Excellence in Comparative Planetology, Hefei, China
⁶Hypervelocity Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang, China
⁷National Key Laboratory of Aerospace Physics in Fluids, Mianyang, China
⁸Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
⁹State Key Laboratory of Critical Mineral Research and Exploration, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
Published by arrangement with John Wiley & Sons

Impact events involving phyllosilicates, whether present in targets or impactors, are highly probable on various celestial bodies. While impact melting is considered the most important metamorphic feature in shocked phyllosilicates, lack of understanding of this process represents a substantial impediment to constraining shock conditions from melted phyllosilicates and to inferring surface evolution of celestial bodies. To investigate shock metamorphism of phyllosilicates, cratering experiments were conducted on clinochlore targets using a light-gas gun at impact velocities ranging from 0.8 to 7.0 km·s−1, and the shocked fragments were characterized with electron microscopy, X-ray diffraction (XRD), Raman spectroscopy and near-infrared spectroscopy. Clinochlore underwent melting at a low velocity of 0.8 km·s−1 due to localized energy concentration at the micron-scale projectile-target interface. With increasing velocity up to 7.0 km·s−1, the shock-generated glasses evolved from semi-parallel nanofilaments to complex agglutinate-like layers, within which abundant vesicles were present due to shock-induced dehydroxylation. Submicroscopic metallic particles were pervasive in the agglutinate-like layers, possibly owing to melting and solidification of micro-jetted metallic fragments. In line with the morphological characterization results, XRD patterns, near-infrared reflectance spectra and Raman spectra of the shocked fragments also collectively reflect the presence and evolution of the impact glasses. Beneath the impact glasses, shock metamorphism may be indicated by decreased basal spacings of clinochlore in the unmelted matrices. Additionally, olivine bearing exogenous iron composition from projectiles crystallized from high-temperature melts during secondary impacts. This work may provide important constraints for regolith evolution and impact history of extraterrestrial bodies.

¹Dijun Guo,^1,2Yeming Bao,¹Xing Wu,³Shuai Li,^1,2,4Yang Liu,¹Yazhou Yang,¹Yuchen Xu,¹Feng Zhang,^4,5Jianzhong Liu,¹Yongliao Zou
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008690]
¹State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
²University of Chinese Academy of Science, Beijing, China
³Hawaii Institute of Geophysics and Planetology, University of Hawaiʻi at Mānoa, Honolulu, HI, USA
⁴Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei, China
⁵Center for Lunar and Planetary Science, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
Published by arrangement with John Wiley & Sons

Ferroan anorthosite, the dominant component of the primordial lunar crust, provides valuable evidence for the lunar magma ocean (LMO) theory. Despite its adjacency to the feldspathic highlands terrane, the identification of pure anorthosite in the Apollo basin has been scarce. Through a comprehensive investigation with high-resolution Kaguya Multiband Imager data over the Apollo basin, we identified numerous outcrops exhibiting definitive diagnostic absorption indicative of the presence of ferroan anorthosite. These anorthosite exposures suggest that crustal material remained after the South Pole-Aitken (SPA) basin impact and that the mafic-rich SPA ejecta was thin in the area, providing significant insights into the excavation process of the SPA impact and subsequent evolution. Our results suggest that the Chang’e-6 mission could potentially bring back the primordial crustal anorthosite from the Apollo basin and offer valuable insights into the LMO theory, alongside the mantle material excavated by the massive SPA impact.

¹Alice C. Quillen,¹Sean Doran
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.70006]
¹Department of Physics and Astronomy, University of Rochester, Rochester, New York, USA
Published by arrangement with John Wiley & Sons

We measure ejecta mass as a function of azimuthal and impact angle for 104 m/s oblique impacts into sand. We find that the ejecta mass distribution is strongly sensitive to azimuthal angle, with as high as eight times more mass in ejecta on the downrange side compared to the uprange side. Crater radii, measured from the impact point, are measured at different impact and azimuthal angles. Crater ejecta scaling laws are modified to depend on azimuthal and impact angle. We find that crater radii are sensitive to both impact and azimuthal angle, but the ejecta mass as a function of both angles can be estimated from the cube of the crater radius without an additional angular dependent function. The ejecta distributions are relevant for processes that depend upon the integrated properties of approximately 100 m/s impacts occurring in the outer solar system and possibly during planetesimal formation.

¹Qin Zhou et al. (>10)
Nature 643, 371-375 Open Access Link to Article [DOI https://doi.org/10.1038/s41586-025-09131-7]
¹Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China

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¹Huicun He et al. (>10)
Nature 643, 366-370 Open Access Link to Article [DOI https://doi.org/10.1038/s41586-025-08870-x]
¹Key Laboratory of the Earth and Planetary Physics, Chinese Academy of Sciences, Beijing, China

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^1,2Shuhui Cai et al. (>10)
Nature 643, 361-365 Open Access Link to Article [DOI https://doi.org/10.1038/s41586-024-08526-2]
¹State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
²College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China

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