학술논문
A pristine record of outer Solar System materials from asteroid Ryugu’s returned sample
Document Type
Original Paper
Author
Ito, Motoo; Tomioka, Naotaka; Uesugi, Masayuki; Yamaguchi, Akira; Shirai, Naoki; Ohigashi, Takuji; Liu, Ming-Chang; Greenwood, Richard C.; Kimura, Makoto; Imae, Naoya; Uesugi, Kentaro; Nakato, Aiko; Yogata, Kasumi; Yuzawa, Hayato; Kodama, Yu; Tsuchiyama, Akira; Yasutake, Masahiro; Findlay, Ross; Franchi, Ian A.; Malley, James A.; McCain, Kaitlyn A.; Matsuda, Nozomi; McKeegan, Kevin D.; Hirahara, Kaori; Takeuchi, Akihisa; Sekimoto, Shun; Sakurai, Ikuya; Okada, Ikuo; Karouji, Yuzuru; Arakawa, Masahiko; Fujii, Atsushi; Fujimoto, Masaki; 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; Mori, Osamu; 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; Tsukizaki, Ryudo; Wada, Koji; Yamada, Manabu; Yamada, Tetsuya; Yamamoto, Yukio; Yano, Hajime; Yokota, Yasuhiro; Yoshihara, Keisuke; Yoshikawa, Makoto; Yoshikawa, Kent; Fukai, Ryota; Furuya, Shizuho; Hatakeda, Kentaro; Hayashi, Tasuku; Hitomi, Yuya; Kumagai, Kazuya; Miyazaki, Akiko; Nishimura, Masahiro; Soejima, Hiromichi; Iwamae, Ayako; Yamamoto, Daiki; Yoshitake, Miwa; Yada, Toru; Abe, Masanao; Usui, Tomohiro; Watanabe, Sei-ichiro; Tsuda, Yuichi
Source
Nature Astronomy. 6(10):1163-1171
Subject
Language
English
ISSN
2397-3366
Abstract
Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of ~30 °C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition.
The sample taken from carbonaceous asteroid Ryugu and brought back to Earth by the Hayabusa2 spacecraft contains outer Solar System-derived materials uncontaminated by terrestrial processes. Even CI carbonaceous chondrites, despite their closeness to solar abundances, are not pristine.
The sample taken from carbonaceous asteroid Ryugu and brought back to Earth by the Hayabusa2 spacecraft contains outer Solar System-derived materials uncontaminated by terrestrial processes. Even CI carbonaceous chondrites, despite their closeness to solar abundances, are not pristine.