Infrared absorption spectra from organic matter in the asteroid Ryugu samples: Some unique properties compared to unheated carbonaceous chondrites
Yoko Kebukawa, É. Quirico, E. Dartois, Hikaru Yabuta, Laure Bejach, L. Bonal, Alexandre Dazzi, Ariane Deniset‐Besseau, J. Duprat, C. Engrand, Jérémie Mathurin, Jens Barosch, George D. Cody, B. T. De Gregorio, Minako Hashiguchi, Kanami Kamide, A. L. D. Kilcoyne, M. Komatsu, Zita Martins, Gilles Montagnac, S. Mostefaoui, L. R. Nittler, Takuji Ohigashi, Taiga Okumura, Laurent Rémusat, Scott A. Sandford, Miho Shigenaka, R. M. Stroud, Hiroki Suga, Yoshio Takahashi, Yasuo Takeichi, Y. Tamenori, Maximilien Verdier‐Paoletti, Daisuke Wakabayashi, Shohei Yamashita, Hisayoshi Yurimoto, Tomoki Nakamura, T. Noguchi, Ryuji Okazaki, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei‐ichiro Watanabe, Yuichi Tsuda
Abstract
Abstract The infrared spectral characteristics of organic‐rich acid residues prepared from Ryugu samples returned by the JAXA Hayabusa2 mission generally match those from unheated carbonaceous chondrite meteorites, but the residues from Ryugu are richer in methyl and methylene functional groups and have higher CH 2 /CH 3 ratios. Moreover, two distinct outlier carbonaceous phases are found; one with spectral characteristics of N‐H functional groups, likely amides, and a second phase containing less nitrogen. Such infrared characteristics of Ryugu organic matter might indicate the pristine nature of the freshly collected samples and reflect the near‐surface chemistry in the parent asteroid.