Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth
Shogo Tachibana, Hirotaka Sawada, Ryuji Okazaki, Yoshinori Takano, Kanako Sakamoto, Yayoi N. Miura, Chisato Okamoto, Hajime Yano, S. Yamanouchi, Patrick Michel, Yun Zhang, S. R. Schwartz, Florian Thuillet, Hisayoshi Yurimoto, Tomoki Nakamura, T. Noguchi, Hikaru Yabuta, Hiroshi Naraoka, A. Tsuchiyama, Naoya Imae, Kosuke Kurosawa, A. Nakamura, Kazunori Ogawa, Seiji Sugita, Tomokatsu Morota, Rie Honda, Shingo Kameda, Eri Tatsumi, Yuichiro Cho, Kazuo Yoshioka, Y. Yokota, Masahiko Hayakawa, M. Matsuoka, Naoya Sakatani, Manabu Yamada, Toru Kouyama, Hidehiko Suzuki, Chikatoshi Honda, Tetsuo Yoshimitsu, Takuji Kubota, H. Demura, Toru Yada, Masahiro Nishimura, Kasumi Yogata, Aiko Nakato, Miwa Yoshitake, Ayako Suzuki, Shizuho Furuya, Kentaro Hatakeda, Akiko Miyazaki, Kazuya Kumagai, Tatsuaki Okada, Masanao Abe, Tomohiro Usui, T. R. Ireland, M. Fujimoto, Tetsuya Yamada, Masahiko Arakawa, H. C. Connolly, Atsushi Fujii, Sunao Hasegawa, Naoyuki Hirata, Naru Hirata, Chikako Hirose, S Hosoda, Y. Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Shota Kikuchi, K. Kitazato, D. S. Lauretta, G. Libourel, Bernard Marty, Koji Matsumoto, Tatsuhiro Michikami, Yuya Mimasu, Akira Miura, Osamu Mori, K. Nakamura‐Messenger, Noriyuki Namiki, A. N. Nguyen, L. R. Nittler, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Go Ono, Masanobu Ozaki, Hiroki Senshu, Takanobu Shimada, Yuri Shimaki, K. Shirai, Stefania Soldini, T. Takahashi, Yuto Takei, Hiroshi Takeuchi, Ryudo Tsukizaki, Koji Wada, Yukio Yamamoto
Abstract
The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.