Tetsuya Yokoyama, Kazuhide Nagashima, Izumi Nakai, Edward D Young, Yoshinari Abe, Jérôme Aléon, Conel M O’D Alexander, Sachiko Amari, Yuri Amelin, Ken-ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W Carlson, Marc Chaussidon, Byeon-Gak Choi, Nicolas Dauphas, Andrew M Davis, Tommaso Di Rocco, Wataru Fujiya, Ryota Fukai, Ikshu Gautam, Makiko K Haba, Yuki Hibiya, Hiroshi Hidaka, Hisashi Homma, Peter Hoppe, Gary R Huss, Kiyohiro Ichida, Tsuyoshi Iizuka, Trevor R Ireland, Akira Ishikawa, Motoo Ito, Shoichi Itoh, Noriyuki Kawasaki, Noriko T Kita, Kouki Kitajima, Thorsten Kleine, Shintaro Komatani, Alexander N Krot, Ming-Chang Liu, Yuki Masuda, Kevin D McKeegan, Mayu Morita, Kazuko Motomura, Frédéric Moynier, Ann Nguyen, Larry Nittler, Morihiko Onose, Andreas Pack, Changkun Park, Laurette Piani, et al.
Science, 2022
Voir en ligne : https://doi-org.insu.bib.cnrs.fr/10.1126/science.abn7850
Abstract :
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 measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to 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, 5.2+0.7−0.8 (Stat.) +1.6−2.1 (Syst.) million years after 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 the Sun’s photosphere than other natural samples do.