Paquet Marine, Moynier Frederic, Yokoyama Tetsuya, Dai Wei, Hu Yan, 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, Nakai Izumi, Nagashima Kazuhide, Nesvorný David, Nguyen Ann N, 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, Young Edward D, Yui Hiroharu, Zhang Ai-Cheng, Nakamura Tomoki, Naraoka Hiroshi, Noguchi Takaaki, Okazaki Ryuji, Sakamoto Kanako, Yabuta Hikaru, Abe Masanao, Miyazaki Akiko, Nakato Aiko, Nishimura Masahiro, Okada Tatsuaki, Yada Toru, Yogata Kasumi, Nakazawa Satoru, Saiki Takanao, Tanaka Satoshi, Terui Fuyuto, Tsuda Yuichi, Watanabe Sei-Ichiro, Yoshikawa Makoto, Tachibana Shogo, Yurimoto Hisayoshi
Université Paris Cité, Institut de physique du globe de Paris, CNRS; 75005 Paris, France.
Department of Earth and Planetary Sciences, Tokyo Institute of Technology; Tokyo 152-8551, Japan.
Nat Astron. 2022 Dec 12;7(2):182-189. doi: 10.1038/s41550-022-01846-1.
Initial analyses showed that asteroid Ryugu's composition is close to CI (Ivuna-like) carbonaceous chondrites -the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (e.g., Ti, Cr) overlap with other carbonaceous chondrite (CC) groups, so the details of the link between Ryugu and the CI chondrites are not fully clear yet. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugu's pristine samples match the solar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earth's mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites, suggesting a contribution of Ryugu-like material to Earth's budgets of Zn and other moderately volatile elements.
初步分析表明，小行星龙宫的成分与CI（类伊武纳）碳质球粒陨石相近——CI碳质球粒陨石是化学组成上最原始的陨石，其大多数元素的丰度接近太阳。然而，一些同位素特征（如Ti、Cr）与其他碳质球粒陨石（CC）群重叠，因此龙宫与CI球粒陨石之间联系的细节尚不完全清楚。在此我们表明，龙宫和CI球粒陨石具有相同的锌和铜同位素组成。由于各种球粒陨石群具有非常独特的锌和铜同位素特征，我们的结果表明龙宫和CI球粒陨石有着共同的成因，排除了与其他CC群的任何关联。由于龙宫的原始样本在许多元素上与太阳元素组成相符，它们的锌和铜同位素组成可能是对太阳组成的最佳估计。地球质量无关的锌同位素组成介于龙宫/CC和非碳质球粒陨石之间，这表明类似龙宫的物质对地球锌和其他中度挥发性元素的储量有贡献。
