^1,2Rei Kanemaru (>10)
Scientific Reports, (in Press)
Link to Article [DOI: 10.1038/s41598-026-80300-y]

¹Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa, Japan
²Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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^1,2Wenbo Liu, ^1,2Huan Wang, ¹Yang Cao, ¹Peng Sang, ¹Yaning Liu, ^1,2Baoquan Li
Journal of Instrumentation, 21, P09053
Link to Article [DOI: 10.1088/1748-0221/21/09/P09053]

¹National Space Science Center, Chinese Academy of Sciences, Beijing, China
²University of Chinese Academy of Sciences, Beijing, China
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¹Darío González Picos, ²Ian J. M. Crossfield, ³David Coria, ⁴Joshua Lothringer, ⁵Eric Gaidos, ²Elisabeth A. C. Mills, ¹Sam de Regt, ⁶Donatella Romano, ¹Ignas Snellen
The Astrophysical Journal, 1010, 22
Open Source Link to Article [DOI: 10.3847/1538-4357/ae9bbc]

¹Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA, Leiden, The Netherlands
²Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
³Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
⁴Space Telescope Science Institute, Baltimore, MD, USA
⁵Department of Earth Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
⁶INAF-Osservatorio di Astrofisica e Scienza dello Spazio, Bologna, Italy

Elemental and isotopic abundances are key tracers of planet formation, stellar evolution, and Galactic chemical evolution. Very low-mass stars are particularly interesting in this regard, because unlike more massive or evolved stars their photospheric abundances retain the star’s natal composition. Cool dwarf spectra have historically been challenging to use for measurements of chemical abundances because of the blending of molecular and atomic features. However, recent advances in molecular line lists, atmospheric models, fitting techniques, and IR spectrographs have enabled the successful measurement of elemental and isotopic ratios in a few dozen very-low-mass stars. Here, we present near-IR high-resolution spectroscopy of TRAPPIST-1 covering the fundamental and overtone bands of carbon monoxide and its prominent isotopologues. From the joint analysis of the K-band (CFHT/SPIRou) and M-band (Keck/NIRSPEC) spectra, we derive the first stellar C/O ratio and the first carbon- and oxygen-isotope ratios for this star. We obtain a metallicity of , a C/O ratio of , , and . TRAPPIST-1 has generally solar-like elemental abundances, with a ¹²C/¹³C that is higher than the solar value and may be modestly elevated relative to some nearby cool dwarfs at similar metallicity. While C/O is most tightly constrained by the K band, the isotopic detections are driven by the M-band data.

¹Kimberly Paragas, ¹Heather A. Knutson, ^2,3,4,5,6Renyu Hu, ^1,7,8,9Bethany L. Ehlmann, ¹⁰Aishwarya R. Iyer, ¹¹Sebastian Zieba, ¹²Laura Kreidberg
The Astrophysical Journal Letters, 1011, L8
Open Source Link to Article [DOI: 10.3847/2041-8213/aeb00b]

¹Division of Geological and Planetary Sciences, California Institute of Technology, USA
²Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
³Department of Astronomy & Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
⁴Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802, USA
⁵Institute for Computational and Data Science, The Pennsylvania State University, University Park, PA 16802, USA
⁶Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
⁷Laboratory for Atmospheric & Space Physics, University of Colorado Boulder, CO 80309, USA
⁸Department of Earth Science, University of Colorado Boulder, CO 80309, USA
⁹Department of Astrophysical & Planetary Sciences, University of Colorado Boulder, CO 80309, USA
¹⁰NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
¹¹Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA 02138, USA
¹²Max-Planck-Institut für Astronomie, D-69117 Heidelberg, Germany

The thermal emission spectra of terrestrial exoplanets provide a window into their surface compositions and
corresponding geological processes. Close-in rocky planets orbiting M dwarfs are ideal targets for these studies,
as observations have shown that most have little to no atmosphere. LHS 3844 b is an ultrashort-period super-Earth
orbiting a nearby M dwarf, and is the most favorable target that does not have a dayside magma ocean. We
present an updated JWST/MIRI Low Resolution Spectroscopy emission spectrum (5–12μm) of this planet,
derived from eight new and three archival eclipse observations. We combine these visits to obtain the highest
signal-to-noise ratio (SNR) emission spectrum for any rocky exoplanet thus far, with a median SNR of 29 across
12 wavelength bins. Our data are sensitive to the predicted Si–O stretching feature (the strongest mid-infrared
silicate feature) for a wide range of common materials, and the transparency feature, which is relatively
insensitive to composition and constrains the grain size and porosity of surface materials. We find that
LHS3844 b’s emission spectrum resembles a blackbody shortward of 10 μm, disfavoring the presence of a
transparency feature, and identify a tentative feature (1.9σ−3.5σ) between 10 and 12 μm. If this feature is
astrophysical and not instrumental in nature, it can be matched by a fayalite (the iron end-member of olivine)
surface, but might also be consistent with other candidate planet-forming materials like spinel or silicon carbide.
We discuss possible biases introduced by the wavelength-dependent instrumental ramp, and outline several
strategies to mitigate this effect in future observations of LHS 3844 b.

^1,2Thomas Stephan, ³Jan Leitner, ^1,2,4Andrew M. Davis, ^1,2,5Julie M. Korsmeyer, ^1,2Gavin Fowler, ^1,2,5Liv Mumma, ^1,2Andrew Regula
The Astrophysical Journal, 1011, 209
Open Source Link to Article [DOI: 10.3847/1538-4357/aeb016]

¹Department of the Geophysical Sciences, The University of Chicago, 5734 S Ellis Avenue, Chicago, IL 60637, USA
²Chicago Center for Cosmochemistry, Chicago, IL, USA
³Max Planck Institute for Chemistry, 55128 Mainz, Germany
⁴The Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637, USA
⁵Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA

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¹Leonardos Gkouvelis, ²Michael K. Shepard, ³Paul Helfenstein, ¹Francisco J. Pozuelos, ^4,5,6,7Renyu Hu
The Astronomical Journal, 172, 309
Open Source Link to Article [DOI: 10.3847/1538-3881/aeb6d6]

¹Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008 Granada, Spain
²Department of Physical and Environmental Sciences, Commonwealth University of Pennsylvania, Hartline Science Center, Room 126, Bloomsburg, PA 17815, USA
³Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853-6801, USA
⁴Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
⁵Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802, USA
⁶Institute for Computational and Data Science, The Pennsylvania State University, University Park, PA 16802, USA
⁷Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA

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¹Emily Bonsall, ¹Eileen Tisdall, ¹Christian Schröder
Astrobiology, 26, (in Press)
Link to Article [DOI: 10.1177/15311074261475984]

¹Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
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¹O. Barraud (>10)
Planetary and Space Science, (in Press), 106363 Link to Article [DOI: 10.1016/j.pss.2026.106363]

¹Institute of Space Research, German Aerospace Center (DLR), Berlin, Germany
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¹Manfred Vogt, ¹Daniel Mahr, ²Andreas Pack, ¹Mario Trieloff
Geochimica et Cosmochimica Acta, (in Press), (in Press)
Open Source Link to Article [DOI: 10.1016/j.gca.2026.11.010]

¹Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, INF 234-236, 69120 Heidelberg, Germany
²Geowissenschaftliches Zentrum, Abteilung Geochemie und Isotopengeologie, Georg-August-Universität Göttingen, Goldschmidtstraße 1, 37073 Göttingen, Germany
Copyright Elsevier

The ungrouped iron meteorite Washington County, so far unique for hosting solar-wind derived He and Ne within its metal, contains previously undocumented µm-sized chromite inclusions, extremely enriched in Mn and with highly variable oxygen isotopic compositions. The chromites of ≤ 13 µm in diameter occur as isolated, angular to subangular grains, which are erratically but frequently distributed within the metal of the iron meteorite. 76 inclusions were characterized by SEM–EDS, micro-Raman spectroscopy and electron microprobe analyses as Mn-bearing chromites (FeCr₂O₄), containing several wt% MnO, and manganochromites ((Mn,Fe)(Cr,V)₂O₄) with up to ∼ 27 wt% MnO, representing the Mn-richest natural chromite ever reported. δ¹⁸O, δ¹⁷O and Δ¹⁷O values of ten Mn-bearing chromites and five manganochromites were determined by Secondary Ion Mass Spectrometry (SIMS) to reveal potential genetic associations with other meteorites.

The δ¹⁸O values of individual chromite inclusions, with spatial distances of only a few millimeters, range from −3.52‰ to + 20.38‰, defining a huge measured isotopic spread – unprecedented among differentiated meteorites – while the mean Δ¹⁷O value of −0.07 ± 0.13‰ (2σ) is indistinguishable from the Terrestrial Fractionation Line (TFL). The measured oxygen isotopic spread shows no systematic relationship with chemical composition of the inclusions as both low- and high-Mn chromites show δ¹⁸O variations of ∼ 22‰ and ∼ 24‰, respectively. However, because potential matrix-dependent and other analytical effects cannot be fully quantified, the magnitude of the intrinsic isotopic variability remains uncertain. If a substantial component is intrinsic, the δ¹⁸O and δ¹⁷O variations are consistent with kinetic isotope fractionation during oxygen diffusion when chromites formed by solid-state exsolution within the FeNi metal upon cooling. Δ¹⁷O values overlap with those of enstatite chondrites, aubrites, and other non-carbonaceous (NC) meteorites but differ from most carbonaceous (CC) meteorites. A comparative analysis of oxygen isotope trends in NC versus CC meteorites shows that Δ¹⁷O values support classification of Washington County as NC-iron, suggesting a common formation region in relation to the NC population. Further literature review reveals additional NC-irons (i.e., irons of groups IIAB, IIG, IIIAB, IVA and IAB) that might, like Washington County, contain volume-correlated solar-type noble gases, potentially consistent with more intense exposure to solar irradiation in the inner solar system and incorporation of solar signatures preferentially into NC parent bodies.

^1,2Pau Grèbol-Tomàs, ³Jordi Ibáñez-Insa, ^1,2Josep Maria Trigo-Rodríguez, ³Abigail Jiménez-Franco, ¹Lysa Chizmadia, ^4,5,6Jordi Sort
The Planetary Science Journal, 7, 252
Open Source Link to Article [DOI: 10.3847/PSJ/aeb1ae]

¹Institut de Ciències de l’Espai (ICE-CSIC), C/Can Magrans s/n, Cerdanyola del Vallès, E-08193, Catalonia, Spain
²Institut d’Estudis Espacials de Catalunya (IEEC), C/ Esteve Terradas 1, Parc Mediterrani de Tecnologia (PMT), Campus Baix Llobregat-UPC, Castelldefels, E-08860, Catalonia, Spain
³Geosciences Barcelona (GEO3BCN-CSIC), C/ Lluís Solé i Sabarís s/n, Barcelona, E-08028, Catalonia, Spain
⁴Departament de Física, Universitat Autònoma de Barcelona (UAB), Bellaterra, E-08193, Catalonia, Spain
⁵Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Bellaterra, E-08193, Catalonia, Spain
⁶Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona, E-08010, Catalonia, Spain
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