¹David Leiser,¹Christian Dürnhofer,¹Erik Poloni,¹Stefan Löhle,²Pavol Matlovič,²Juraj Tóth,³Jérémie Vaubaillon
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115867]
¹High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, Stuttgart, 70569, Germany
²Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F1, Bratislava, 842 48, Slovakia
³IMCCE, CNRS, Observatoire de Paris, PSL Université, Sorbonne Université, Université de Lille 1, UMR 8028 du CNRS, 77 Av. Denfert Rochereau, Paris, 75014, France
Copyright Elsevier

Ground testing meteorite samples offer in-situ measurements of known materials in conditions that occur during entry into Earth’s atmosphere. 22 meteorite samples with a wide range of origins and classifications were tested in the plasma wind tunnel facility PWK1 at the Institute of Space Systems in Stuttgart. These tests recreate the flow condition of a meteoroid during entry into earth’s atmosphere at an altitude of 78.8 km altitude and a velocity of 11.7 km s-1. Four optical diagnostic techniques were used to measure the surface temperature above 1000 K. 2-D methods showed that the surface temperature is evenly distributed over the sample surface, while time-resolved analyses show that the samples reach a steady state temperature within 0.5 s. The steady-state temperature for chondritic samples was consistent but varied significantly for achondrites and iron meteorite samples. The composition data showed a strong dependency of the surface temperature on the silicon content. The surface temperatures were shown to be dependent on the material and a database of temperatures was set up. The Planck fit methodology could be directly adapted to spectral meteor observation systems. A comparison of the method to established methods showed an offset between the methods. This data could be applied to thermal models to better understand the energy transfer processes during meteor flight.

¹Eric Quirico et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14097]
¹Institut de Planétologie et d’Astrophysique (IPAG), UMR 5274, CNRS, Université Grenoble Alpes, Grenoble, France
Published by arrangement with John Wiley & Sons

We report a Fourier transform infrared analysis of functional groups in insoluble organic matter (IOM) extracted from a series of 100–500 μm Ryugu grains collected during the two touchdowns of February 22 and July 11, 2019. IOM extracted from most of the samples is very similar to IOM in primitive CI, CM, and CR chondrites, and shows that the extent of thermal metamorphism in Ryugu regolith was, at best, very limited. One sample displays chemical signatures consistent with a very mild heating, likely due to asteroidal collision impacts. We also report a lower carbonyl abundance in Ryugu IOM samples compared to primitive chondrites, which could reflect the accretion of a less oxygenated precursor by Ryugu. The possible effects of hydrothermal alteration and terrestrial weathering are also discussed. Last, no firm conclusions could be drawn on the origin of the soluble outlier phases, observed along with IOM in this study and in the preliminary analysis of Ryugu samples. However, it is clear that the HF/HCl residues presented in this publication are a mix between IOM and the nitrogen-rich outlier phase.