Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites
Authors: Yokoyama Tetsuya , Nagashima Kazuhide , Nakai Izumi , Young Edward D. , Abe Yoshinari , Aléon Jérôme , Alexander Conel M. O’D. , Amari Sachiko , Amelin Yuri , Bajo Ken-ichi , Bizzarro Martin , Bouvier Audrey , Carlson Richard W. , Chaussidon Marc , Choi Byeon-Gak , Dauphas Nicolas , Davis Andrew M. , Di Rocco Tommaso , Fujiya Wataru , Fukai Ryota , Gautam Ikshu , Haba Makiko K. , Hibiya Yuki , Hidaka Hiroshi , Homma Hisashi , Hoppe Peter , Huss Gary R. , Ichida Kiyohiro , Iizuka Tsuyoshi , Ireland Trevor R. , Ishikawa Akira , Ito Motoo , Itoh Shoichi , Kawasaki Noriyuki , Kita Noriko T. , Kitajima Kouki , Kleine Thorsten , Komatani Shintaro , Krot Alexander N. , Liu Ming-Chang , Masuda Yuki , McKeegan Kevin D. , Morita Mayu , Motomura Kazuko , Moynier Frédéric , Nguyen Ann , Nittler Larry , Onose Morihiko , Pack Andreas , Park Changkun , Piani Laurette , Qin Liping , Russell Sara S. , Sakamoto Naoya , Schönbächler Maria , Tafla Lauren , Tang Haolan , Terada Kentaro , Terada Yasuko , Usui Tomohiro , Wada Sohei , Wadhwa Meenakshi , Walker Richard J. , Yamashita Katsuyuki , Yin Qing-Zhu , Yoneda Shigekazu , Yui Hiroharu , Zhang Ai-Cheng , Connolly Harold C. , Lauretta Dante S. , Nakamura Tomoki , Naraoka Hiroshi , Noguchi Takaaki , Okazaki Ryuji , Sakamoto Kanako , Yabuta Hikaru , Abe Masanao , Arakawa Masahiko , Fujii Atsushi , Hayakawa Masahiko , Hirata Naoyuki , Hirata Naru , Honda Rie , Honda Chikatoshi , Hosoda Satoshi , Iijima Yu-ichi , Ikeda Hitoshi , Ishiguro Masateru , Ishihara Yoshiaki , Iwata Takahiro , Kawahara Kosuke , Kikuchi Shota , Kitazato Kohei , Matsumoto Koji , Matsuoka Moe , Michikami Tatsuhiro , Mimasu Yuya , Miura Akira , Morota Tomokatsu , Nakazawa Satoru , Namiki Noriyuki , Noda Hirotomo , Noguchi Rina , Ogawa Naoko , Ogawa Kazunori , Okada Tatsuaki , Okamoto Chisato , Ono Go , Ozaki Masanobu , Saiki Takanao , Sakatani Naoya , Sawada Hirotaka , Senshu Hiroki , Shimaki Yuri , Shirai Kei , Sugita Seiji , Takei Yuto , Takeuchi Hiroshi , Tanaka Satoshi , Tatsumi Eri , Terui Fuyuto , Tsuda Yuichi , Tsukizaki Ryudo , Wada Koji , Watanabe Sei-ichiro , Yamada Manabu , Yamada Tetsuya , Yamamoto Yukio , Yano Hajime , Yokota Yasuhiro , Yoshihara Keisuke , Yoshikawa Makoto , Yoshikawa Kent , Furuya Shizuho , Hatakeda Kentaro , Hayashi Tasuku , Hitomi Yuya , Kumagai Kazuya , Miyazaki Akiko , Nakato Aiko , Nishimura Masahiro , Soejima Hiromichi , Suzuki Ayako , Yada Toru , Yamamoto Daiki , Yogata Kasumi , Yoshitake Miwa , Tachibana Shogo , Yurimoto Hisayoshi 
Published: June 2022

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about

5.2

−
0.7

+
0.8

million (statistical) or

5.2

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2.1

+
1.6

million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun’s photosphere than other natural samples do.