Reassigning CI chondrite parent bodies based on reflectance spectroscopy of samples from carbonaceous asteroid Ryugu and meteoritesOPEN ACCESS

06/12/2023 23:21 · by karmaka · in asteroid, carbonaceous chondrite, CI, Hayabusa-2 / 162173 Ryugu, parent body, reflectance spectra

Kana Amano Moe Matsuoka Tomoki Nakamura Eiichi Kagawa Yuri Fujioka Sandra M. Potin Takahiro Hiroi Eri Tatsumi Ralph E. Milliken Eric Quirico Pierre Beck Rosario Brunetto Masayuki Uesugi Yoshio Takahashi Takahiro Kawai Shohei Yamashita Yuma Enokido Taiga Wada Yoshihiro Furukawa Michael E. Zolensky Driss Takir Deborah L. Domingue Camilo Jaramillo-Correa Faith Vilas Amanda R. Hendrix Mizuha Kikuiri Tomoyo Morita Hisayoshi Yurimoto Takaaki Noguchi Ryuji Okazaki Hikaru Yabuta 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

Science Advances
6 Dec 2023
Vol 9, Issue 49

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“The carbonaceous asteroid Ryugu has been explored by the Hayabusa2 spacecraft to elucidate the actual nature of hydrous asteroids. Laboratory analyses revealed that the samples from Ryugu are comparable to unheated CI carbonaceous chondrites; however, reflectance spectra of Ryugu samples and CIs do not coincide. Here, we demonstrate that Ryugu sample spectra are reproduced by heating Orgueil CI chondrite at 300°C under reducing conditions, which caused dehydration of terrestrial weathering products and reduction of iron in phyllosilicates. Terrestrial weathering of CIs accounts for the spectral differences between Ryugu sample and CIs, which is more severe than space weathering that likely explains those between asteroid Ryugu and the collected samples. Previous assignments of CI chondrite parent bodies, i.e., chemically most primitive objects in the solar system, are based on the spectra of CI chondrites. This study indicates that actual spectra of CI parent bodies are much darker and flatter at ultraviolet to visible wavelengths than the spectra of CI chondrites.”