In situ investigation of an organic micro-globule and its mineralogical context within a Ryugu “sand” grain

Phan, V. T. H. et al. (2024) In situ investigation of an organic micro-globule and its mineralogical context within a Ryugu “sand” grain. Meteoritics and Planetary Science, (doi: 10.1111/maps.14122) (Early Online Publication)

Abstract

The Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA) returned to the Earth samples of carbonaceous asteroid (162173) Ryugu. This mission offers a unique opportunity to investigate in the laboratory samples from a C-type asteroid, without physical or chemical alteration by the terrestrial atmosphere. Here, we report on an investigation of the mineralogy and the organo-chemistry of Hayabusa2 samples using a combination of micro- and nano-infrared spectroscopy. Particles investigated with conventional FTIR spectroscopy have spectra dominated by phyllosilicate-related absorption, as observed for samples of CI-chondrites, selected ungrouped carbonaceous chondrites, and selected hydrated micrometeorites. Ryugu samples show smaller sulfate-related absorption than CI-chondrites. Our samples that were only briefly exposed to the Earth atmosphere show absorptions related to molecular water, revealing fast terrestrial contamination of the spectral signature at 3 μm. Overall, our FTIR data are in agreement with other work done on Ryugu samples, revealing a low degree of mineralogical variability across Ryugu samples. AFM-IR mapping of the grains shows the presence of a micrometer-sized organic globule in one of our analyzed grains. The AFM-IR spectra obtained on this globule are similar to IR spectra obtained on IOM suggesting that it is constituted of refractory organic matter. This globule may host silicate in its interior, with a different mineralogy than bulk Ryugu phyllosilicate. The shape, presence of peculiar silicate, and the nature of organic constituting the globule point toward a pre-accretionary origin of this globule and that at least part of Ryugu organics were inherited from the protosolar nebulae or the interstellar media. Altogether, our results show the similarities between Ryugu samples and CI chondrites.

• Item Type: Articles
• Additional Information: The Hayabusa2 project has been developed and led by JAXA in collaboration with Deutsches Zentrum für Luft- und Raumfahrt (DLR) and Centre national d'études spatiales (CNES), and supported by NASA and Australian Space Agency (ASA). The H2020 European Research Council (ERC) (SOLARYS ERC-CoG2017_771691). The Programme National de Planétologie (PNP). The Centre national d’études spatiales (CNES) within the framework of the Hayabusa 2 and MMX missions.
• Status: Early Online Publication
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Daly, Dr Luke and Lee, Professor Martin
• Authors: Phan, V. T. H., Beck, P., Rebois, R., Quirico, E., Noguchi, T., Matsumoto, T., Miyake, A., Igami, Y., Haruta, M., Saito, H., Hata, S., Seto, Y., Miyahara, M., Tomioka, N., Ishii, H. A., Bradley, J. P., Ohtaki, K. K., Dobrică, E., Leroux, H., Le Guillou, C., Jacob, D., de la Peña, F., Laforet, S., Marinova, M., Langenhorst, F., Harries, D., Abreu, N. M., Gray, J., Zega, T., Zanetta, P.-M., Thompson, M. S., Stroud, R., Mathurin, J., Dazzi, A., Dartois, E., Engrand, C., Burgess, K., Cymes, B. A., Bridges, J. C., Hicks, L., Lee, M. R., Daly, L., Bland, P. A., Zolensky, M. E., Frank, D. R., Martinez, J., Tsuchiyama, A., Yasutake, M., Matsuno, J., Okumura, S., Mitsukawa, I., Uesugi, K., Uesugi, M., Takeuchi, A., Sun, M., Enju, S., Takigawa, A., Michikami, T., Nakamura, T., Matsumoto, M., Nakauchi, Y., Abe, M., Nakazawa, S., Okada, T., Saiki, T., Tanaka, S., Terui, F., Yoshikawa, M., Miyazaki, A., Nakato, A., Nishimura, M., Usui, T., Yada, T., Yurimoto, H., Nagashima, K., Kawasaki, N., Sakamotoa, N., Hoppe, P., Okazaki, R., Yabuta, H., Naraoka, H., Sakamoto, K., Tachibana, S., Watanabe, S.-i., and Tsuda, Y.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Meteoritics and Planetary Science
• Publisher: Wiley
• ISSN: 1086-9379
• ISSN (Online): 1945-5100
• Published Online: 08 January 2024
• Copyright Holders: Copyright © 2024 The Authors
• First Published: First published in Meteoritics and Planetary Science 2024
• Publisher Policy: Reproduced under a Creative Commons License