^1,2Druce, M.,^1,2Stirling, C.H.,³Rolison, J.M.
Geostandards and Geoanalytical Research (in Press) Link to Article [DOI: 10.1111/ggr.12341]
¹Department of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand
²Centre for Trace Element Analysis, University of Otago, PO Box 56, Dunedin, New Zealand
³Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States

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¹Ted L.Roush
Icarsu (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2020.114056]
¹Space Sciences Division, NASA Ames Research Center, Planetary Systems Branch, MS 245-3, Moffett Field, CA 94035-1000, United States of America
Copyright Elsevier

The visible, near-, and mid-infrared (≈0.4–6 μm) imaginary indices of refraction (k) are estimated from reflectance spectra for three carbonates germane to martian and terrestrial studies. The resulting values are combined with previous data at longer wavelengths and a subtractive Kramers-Konig analysis is used to estimate the real indices of refraction (n) as a function of wavelength. This process is iterated until neither the n or k vary significantly. The results provide estimated complex refractive indices spanning the ≈0.4–400 μm. The estimated visible, near-, and mid-infrared carbonate complex refractive indices are broadly consistent with previous studies, but extend the wavelength coverage and improve the spectral resolution for these materials.

¹Gordon M.Gartrelle,^1,2Paul S.Hardersen,^1,3Matthew R.M.Izawa,^1,4Matthew C.Nowinski
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2020.114043]
¹University of North Dakota, Grand Forks, ND, USA
²Trouvaille LLC, Tucson, AZ, USA
³Institute of Planetary Materials, Okayama University, Misasa, Japan
⁴The Boeing Company, Washington, DC, USA
Copyright Elsevier

D-type asteroids are a prime example of the many dark, low-albedo asteroids which do not reflect sufficient light to reveal detectable mineral absorptions. While D-type asteroids are relatively rare in the inner solar system and the main asteroid belt, they are dominant among the Jovian Trojans. In this study, we have applied Shkuratov radiative transfer modeling to laboratory spectra of meteorites for which mineral abundances have been measured using X-ray diffraction (XRD) and Rietveld refinement. The general agreement of radiative transfer and XRD estimates of mineral abundances demonstrates the applicability of the radiative transfer approach to featureless, low-albedo spectra. Shkuratov modeling was then applied to new spectral observations of D-type asteroids, along with numerous previously published spectra. The surface mineral abundances of 81 D-type objects, including NASA’s Lucy Mission target (21900) Orus, were modeled using assemblages that are plausible based on meteorite analogues. Modeling results reveal D-types are composed of: low-iron olivine; magnesium saponite-dominant phyllosilicates; opaques such as pyrrhotite and tholin; as well as traces of water-ice and other constituents. Subtle compositional differences in model mineralogies exist between Trojan and non-Trojan D-types as well as between L4 and L5 Trojans suggesting differing formational as well as evolutional conditions have affected these bodies.

¹S. Potin,¹P. Beck,¹L. Bonal,¹B. Schmitt,²A. Garenne,³F. Moynier,⁴A. Agranier,^5,6P. Schmitt‐Kopplin,⁷A. K. Malik,¹E. Quirico
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13540]
¹Institut de Planétologie et d’Astrophysique de Grenoble IPAG, Université Grenoble Alpes, CNRS, 414 rue de la Piscine, 38400 Saint‐Martin d’Hères, France
²Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California, 94550 USA
³Institut de Physique du Globe de Paris, Université de Paris, CNRS, 1 rue Jussieu, 75005 Paris, France
⁴Laboratoire Géosciences Océan, UMR/CNRS 6538, IUEM, Université de Bretagne Occidentale, Technopôle Brest‐Iroise, Rue Dumont d’Urville, 29280 Plouzané, France
⁵Helmholtz Zentrum Muenchen, Research Unit Environmental Simulation (EUS) Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
⁶Lehrstuhl für Analytische Lebensmittechemie, Technische Universität München, Maximus‐von‐Imhof‐Forum 2, 85354 Freising, Germany
⁷Department of Chemistry, Punjabi University, Patiala, 147 002 Punjab, India
Published by arrangement with John Wiley & Sons

We present here several laboratory analyses performed on the freshly fallen Mukundpura CM chondrite. Results of infrared transmission spectroscopy, thermogravimetry analysis, and reflectance spectroscopy show that Mukundpura is mainly composed of phyllosilicates. The rare earth trace elements composition and ultrahigh‐resolution mass spectrometry of the soluble organic matter give results consistent with CM chondrites. Finally, Raman spectroscopy shows no signs of thermal alteration of the meteorite. All the results agree that Mukundpura has been strongly altered by water on its parent body. Comparison of the results obtained on the meteorite with those of other chondrites of known petrologic types leads to the conclusion that Mukundpura is similar to CM1 chondrites, which differ from its original classification as a CM2.