The parent bodies of Ryugu and Ivuna formed before those of other carbonaceous chondrites
Abstract
Most carbonaceous chondrite (CC) meteorites contain abundant chondrules, millimeter-scale spherical inclusions of previously molten material. Ivuna-type carbonaceous chondrites (CIs) do not contain chondrules, nor do samples of the carbonaceous asteroid Ryugu. CIs and Ryugu share isotopic properties distinct from those of other CCs, implying that their parent bodies formed at a different time or place than those of other CCs. We applied manganese-chromium dating and oxygen isotope thermometry to Ryugu and Ivuna samples. The results indicate that the parent bodies of Ryugu and Ivuna formed less than 2 million years after the beginning of Solar System formation—before the majority of chondrules in CCs and the parent bodies of other CCs formed. This implies that Ryugu and CIs are remnants of an earlier generation of carbonaceous planetesimals.
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Authors: Noriyuki Kawasaki, K. Nagashima, Naoya Sakamoto, Wataru Fujiya, Sota Arakawa, Ken‐ichi Bajo, N. T. Kita, Kouki Kitajima, Alexander N. Krot, G. R. Huss, Yoshinari Abe, J. Aléon, C. M. O'd. Alexander, S. Amari, Yuri Amelin, Martin Bizzarro, Audrey Bouvier, Richard W. Carlson, Marc Chaussidon, Byeon‐Gak Choi, Nicolas Dauphas, A. M. Davis, Tommaso Di Rocco, Ryota Fukai, Ikshu Gautam, Makiko K. Haba, Yuki Hibiya, Hiroshi Hidaka, Hisashi Homma, Tsuyoshi Iizuka, T. R. Ireland, Akira Ishikawa, Shoichi Itoh, T. Kleine, Shintaro Komatani, Ming‐Chang Liu, Yuki Masuda, Kazuko Motomura, Frédéric Moynier, Izumi Nakai, A. N. Nguyen, L. R. Nittler, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, S. S. Russell, Maria Schönbächler, Kentaro Terada, Yasuko Terada, Tomohiro Usui, Sohei Wada, M. Wadhwa, R. J. Walker, Katsuyuki Yamashita, Qing‐Zhu Yin, Tetsuya Yokoyama, Shigekazu Yoneda, Edward Young, Hiroharu Yui, Ai‐Cheng Zhang, Tomoki Nakamura, Hiroshi Naraoka, T. Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tatsuaki Okada, Toru Yada, Kasumi Yogata, Satoru Nakazawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Sei‐ichiro Watanabe, Makoto Yoshikawa, Shogo Tachibana, Hisayoshi Yurimoto
Institutions: University of Chicago, The University of Queensland, Chinese Academy of Sciences, University of Hong Kong, Kyoto University, The University of Osaka, University of Göttingen, University of Copenhagen, The University of Tokyo, Kyushu University, University of Hawaiʻi at Mānoa, Université Paris Cité, Sorbonne Université, Hokkaido University, Japan Synchrotron Radiation Research Institute, Tohoku University, University of Maryland, College Park, Nanjing University, University of Wisconsin–Madison, Arizona State University, Nagoya University, University of Science and Technology of China, University of California, Davis, Seoul National University of Education, Planetary Science Institute, University of Bayreuth, Japan Agency for Marine-Earth Science and Technology, Okayama University, Institut de physique du globe de Paris, Hiroshima University, Hokkaido University of Science, Natural History Museum, Tokyo University of Science, Kanagawa Institute of Technology, Carnegie Institution for Science, Max Planck Institute for Solar System Research, Osaka Health Science University, Tokyo Denki University, Japan Aerospace Exploration Agency, Lawrence Livermore National Laboratory, Johnson Space Center, Planetary Systems (United States), Institute of Space and Astronautical Science, Guangzhou Institute of Geochemistry, National Museum of Nature and Science, Korea Polar Research Institute, Board of the Swiss Federal Institutes of Technology, Muséum national d'Histoire naturelle, Ibaraki University, Rigaku (Japan), Horiba (Japan), Centre de Recherches Pétrographiques et Géochimiques