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1. Collisional history of Ryugu’s parent body from bright surface boulders

Author

Tatsumi, E., Sugimoto, C., Riu, L., Sugita, S., Nakamura, T., Hiroi, T., Morota, T., Popescu, M., Michikami, T., Kitazato, K., Matsuoka, M., Kameda, S., Honda, R., Yamada, M., Sakatani, N., Kouyama, T., Yokota, Y., Honda, C., Suzuki, H., Cho, Y., Ogawa, K., Hayakawa, M., Sawada, H., Yoshioka, K., Pilorget, C., Ishida, M., Domingue, D., Hirata, N., Sasaki, S., de León, J., Barucci, M. A., Michel, P., Suemitsu, M., Saiki, T., Tanaka, S., Terui, F., Nakazawa, S., Kikuchi, S., Yamaguchi, T., Ogawa, N., Ono, G., Mimasu, Y., Yoshikawa, K., Takahashi, T., Takei, Y., Fujii, A., Yamamoto, Y., Okada, T., Hirose, C., Hosoda, S., Mori, O., Shimada, T., Soldini, S., Tsukizaki, R., Mizuno, T., Iwata, T., Yano, H., Ozaki, M., Abe, M., Ohtake, M., Namiki, N., Tachibana, S., Arakawa, M., Ikeda, H., Ishiguro, M., Wada, K., Yabuta, H., Takeuchi, H., Shimaki, Y., Shirai, K., Hirata, N., Iijima, Y., Tsuda, Y., Watanabe, S., and Yoshikawa, M.

Published
2021
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2. Detailed Images of Asteroid 25143 Itokawa from Hayabusa

Author

Saito, J., Miyamoto, H., Nakamura, R., Ishiguro, M., Michikami, T., Nakamura, A. M., Demura, H., Sasaki, S., Hirata, N., Honda, C., Yamamoto, A., Yokota, Y., Fuse, T., Yoshida, F., Tholen, D. J., Gaskell, R. W., Hashimoto, T., Kubota, T., Higuchi, Y., Nakamura, T., Smith, P., Hiraoka, K., Honda, T., Kobayashi, S., Furuya, M., Matsumoto, N., Nemoto, E., Yukishita, A., Kitazato, K., Dermawan, B., Sogame, A., Terazono, J., Shinohara, C., and Akiyama, H.

Published
2006

3. Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Author

Nakamura, T., primary, Matsumoto, M., additional, Amano, K., additional, Enokido, Y., additional, Zolensky, M. E., additional, Mikouchi, T., additional, Genda, H., additional, Tanaka, S., additional, Zolotov, M. Y., additional, Kurosawa, K., additional, Wakita, S., additional, Hyodo, R., additional, Nagano, H., additional, Nakashima, D., additional, Takahashi, Y., additional, Fujioka, Y., additional, Kikuiri, M., additional, Kagawa, E., additional, Matsuoka, M., additional, Brearley, A. J., additional, Tsuchiyama, A., additional, Uesugi, M., additional, Matsuno, J., additional, Kimura, Y., additional, Sato, M., additional, Milliken, R. E., additional, Tatsumi, E., additional, Sugita, S., additional, Hiroi, T., additional, Kitazato, K., additional, Brownlee, D., additional, Joswiak, D. J., additional, Takahashi, M., additional, Ninomiya, K., additional, Takahashi, T., additional, Osawa, T., additional, Terada, K., additional, Brenker, F. E., additional, Tkalcec, B. J., additional, Vincze, L., additional, Brunetto, R., additional, Aléon-Toppani, A., additional, Chan, Q. H. S., additional, Roskosz, M., additional, Viennet, J.-C., additional, Beck, P., additional, Alp, E. E., additional, Michikami, T., additional, Nagaashi, Y., additional, Tsuji, T., additional, Ino, Y., additional, Martinez, J., additional, Han, J., additional, Dolocan, A., additional, Bodnar, R. J., additional, Tanaka, M., additional, Yoshida, H., additional, Sugiyama, K., additional, King, A. J., additional, Fukushi, K., additional, Suga, H., additional, Yamashita, S., additional, Kawai, T., additional, Inoue, K., additional, Nakato, A., additional, Noguchi, T., additional, Vilas, F., additional, Hendrix, A. R., additional, Jaramillo-Correa, C., additional, Domingue, D. L., additional, Dominguez, G., additional, Gainsforth, Z., additional, Engrand, C., additional, Duprat, J., additional, Russell, S. S., additional, Bonato, E., additional, Ma, C., additional, Kawamoto, T., additional, Wada, T., additional, Watanabe, S., additional, Endo, R., additional, Enju, S., additional, Riu, L., additional, Rubino, S., additional, Tack, P., additional, Takeshita, S., additional, Takeichi, Y., additional, Takeuchi, A., additional, Takigawa, A., additional, Takir, D., additional, Tanigaki, T., additional, Taniguchi, A., additional, Tsukamoto, K., additional, Yagi, T., additional, Yamada, S., additional, Yamamoto, K., additional, Yamashita, Y., additional, Yasutake, M., additional, Uesugi, K., additional, Umegaki, I., additional, Chiu, I., additional, Ishizaki, T., additional, Okumura, S., additional, Palomba, E., additional, Pilorget, C., additional, Potin, S. M., additional, Alasli, A., additional, Anada, S., additional, Araki, Y., additional, Sakatani, N., additional, Schultz, C., additional, Sekizawa, O., additional, Sitzman, S. D., additional, Sugiura, K., additional, Sun, M., additional, Dartois, E., additional, De Pauw, E., additional, Dionnet, Z., additional, Djouadi, Z., additional, Falkenberg, G., additional, Fujita, R., additional, Fukuma, T., additional, Gearba, I. R., additional, Hagiya, K., additional, Hu, M. Y., additional, Kato, T., additional, Kawamura, T., additional, Kimura, M., additional, Kubo, M. K., additional, Langenhorst, F., additional, Lantz, C., additional, Lavina, B., additional, Lindner, M., additional, Zhao, J., additional, Vekemans, B., additional, Baklouti, D., additional, Bazi, B., additional, Borondics, F., additional, Nagasawa, S., additional, Nishiyama, G., additional, Nitta, K., additional, Mathurin, J., additional, Matsumoto, T., additional, Mitsukawa, I., additional, Miura, H., additional, Miyake, A., additional, Miyake, Y., additional, Yurimoto, H., additional, Okazaki, R., additional, Yabuta, H., additional, Naraoka, H., additional, Sakamoto, K., additional, Tachibana, S., additional, Connolly, H. C., additional, Lauretta, D. S., additional, Yoshitake, M., additional, Yoshikawa, M., additional, Yoshikawa, K., additional, Yoshihara, K., additional, Yokota, Y., additional, Yogata, K., additional, Yano, H., additional, Yamamoto, Y., additional, Yamamoto, D., additional, Yamada, M., additional, Yamada, T., additional, Yada, T., additional, Wada, K., additional, Usui, T., additional, Tsukizaki, R., additional, Terui, F., additional, Takeuchi, H., additional, Takei, Y., additional, Iwamae, A., additional, Soejima, H., additional, Shirai, K., additional, Shimaki, Y., additional, Senshu, H., additional, Sawada, H., additional, Saiki, T., additional, Ozaki, M., additional, Ono, G., additional, Okada, T., additional, Ogawa, N., additional, Ogawa, K., additional, Noguchi, R., additional, Noda, H., additional, Nishimura, M., additional, Namiki, N., additional, Nakazawa, S., additional, Morota, T., additional, Miyazaki, A., additional, Miura, A., additional, Mimasu, Y., additional, Matsumoto, K., additional, Kumagai, K., additional, Kouyama, T., additional, Kikuchi, S., additional, Kawahara, K., additional, Kameda, S., additional, Iwata, T., additional, Ishihara, Y., additional, Ishiguro, M., additional, Ikeda, H., additional, Hosoda, S., additional, Honda, R., additional, Honda, C., additional, Hitomi, Y., additional, Hirata, N., additional, Hayashi, T., additional, Hayakawa, M., additional, Hatakeda, K., additional, Furuya, S., additional, Fukai, R., additional, Fujii, A., additional, Cho, Y., additional, Arakawa, M., additional, Abe, M., additional, and Tsuda, Y., additional

Published
2023
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5. Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

Author

Tachibana, S., primary, Sawada, H., additional, Okazaki, R., additional, Takano, Y., additional, Sakamoto, K., additional, Miura, Y. N., additional, Okamoto, C., additional, Yano, H., additional, Yamanouchi, S., additional, Michel, P., additional, Zhang, Y., additional, Schwartz, S., additional, Thuillet, F., additional, Yurimoto, H., additional, Nakamura, T., additional, Noguchi, T., additional, Yabuta, H., additional, Naraoka, H., additional, Tsuchiyama, A., additional, Imae, N., additional, Kurosawa, K., additional, Nakamura, A. M., additional, Ogawa, K., additional, Sugita, S., additional, Morota, T., additional, Honda, R., additional, Kameda, S., additional, Tatsumi, E., additional, Cho, Y., additional, Yoshioka, K., additional, Yokota, Y., additional, Hayakawa, M., additional, Matsuoka, M., additional, Sakatani, N., additional, Yamada, M., additional, Kouyama, T., additional, Suzuki, H., additional, Honda, C., additional, Yoshimitsu, T., additional, Kubota, T., additional, Demura, H., additional, Yada, T., additional, Nishimura, M., additional, Yogata, K., additional, Nakato, A., additional, Yoshitake, M., additional, Suzuki, A. I., additional, Furuya, S., additional, Hatakeda, K., additional, Miyazaki, A., additional, Kumagai, K., additional, Okada, T., additional, Abe, M., additional, Usui, T., additional, Ireland, T. R., additional, Fujimoto, M., additional, Yamada, T., additional, Arakawa, M., additional, Connolly, H. C., additional, Fujii, A., additional, Hasegawa, S., additional, Hirata, N., additional, Hirose, C., additional, Hosoda, S., additional, Iijima, Y., additional, Ikeda, H., additional, Ishiguro, M., additional, Ishihara, Y., additional, Iwata, T., additional, Kikuchi, S., additional, Kitazato, K., additional, Lauretta, D. S., additional, Libourel, G., additional, Marty, B., additional, Matsumoto, K., additional, Michikami, T., additional, Mimasu, Y., additional, Miura, A., additional, Mori, O., additional, Nakamura-Messenger, K., additional, Namiki, N., additional, Nguyen, A. N., additional, Nittler, L. R., additional, Noda, H., additional, Noguchi, R., additional, Ogawa, N., additional, Ono, G., additional, Ozaki, M., additional, Senshu, H., additional, Shimada, T., additional, Shimaki, Y., additional, Shirai, K., additional, Soldini, S., additional, Takahashi, T., additional, Takei, Y., additional, Takeuchi, H., additional, Tsukizaki, R., additional, Wada, K., additional, Yamamoto, Y., additional, Yoshikawa, K., additional, Yumoto, K., additional, Zolensky, M. E., additional, Nakazawa, S., additional, Terui, F., additional, Tanaka, S., additional, Saiki, T., additional, Yoshikawa, M., additional, Watanabe, S., additional, and Tsuda, Y., additional

Published
2022
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6. Geologic History and Crater Morphology of Asteroid (162173) Ryugu

Author

Cho, Y., primary, Morota, T., additional, Kanamaru, M., additional, Takaki, N., additional, Yumoto, K., additional, Ernst, C. M., additional, Hirabayashi, M., additional, Barnouin, O. S., additional, Tatsumi, E., additional, Otto, K. A., additional, Schmitz, N., additional, Wagner, R. J., additional, Jaumann, R., additional, Miyamoto, H., additional, Kikuchi, H., additional, Hemmi, R., additional, Honda, R., additional, Kameda, S., additional, Yokota, Y., additional, Kouyama, T., additional, Suzuki, H., additional, Yamada, M., additional, Sakatani, N., additional, Honda, C., additional, Hayakawa, M., additional, Yoshioka, K., additional, Matsuoka, M., additional, Michikami, T., additional, Hirata, N., additional, Sawada, H., additional, Ogawa, K., additional, and Sugita, S., additional

Published
2021
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8. Collisional history of Ryugu’s parent body from bright surface boulders

Author

Tatsumi, E., primary, Sugimoto, C., additional, Riu, L., additional, Sugita, S., additional, Nakamura, T., additional, Hiroi, T., additional, Morota, T., additional, Popescu, M., additional, Michikami, T., additional, Kitazato, K., additional, Matsuoka, M., additional, Kameda, S., additional, Honda, R., additional, Yamada, M., additional, Sakatani, N., additional, Kouyama, T., additional, Yokota, Y., additional, Honda, C., additional, Suzuki, H., additional, Cho, Y., additional, Ogawa, K., additional, Hayakawa, M., additional, Sawada, H., additional, Yoshioka, K., additional, Pilorget, C., additional, Ishida, M., additional, Domingue, D., additional, Hirata, N., additional, Sasaki, S., additional, de León, J., additional, Barucci, M. A., additional, Michel, P., additional, Suemitsu, M., additional, Saiki, T., additional, Tanaka, S., additional, Terui, F., additional, Nakazawa, S., additional, Kikuchi, S., additional, Yamaguchi, T., additional, Ogawa, N., additional, Ono, G., additional, Mimasu, Y., additional, Yoshikawa, K., additional, Takahashi, T., additional, Takei, Y., additional, Fujii, A., additional, Yamamoto, Y., additional, Okada, T., additional, Hirose, C., additional, Hosoda, S., additional, Mori, O., additional, Shimada, T., additional, Soldini, S., additional, Tsukizaki, R., additional, Mizuno, T., additional, Iwata, T., additional, Yano, H., additional, Ozaki, M., additional, Abe, M., additional, Ohtake, M., additional, Namiki, N., additional, Tachibana, S., additional, Arakawa, M., additional, Ikeda, H., additional, Ishiguro, M., additional, Wada, K., additional, Yabuta, H., additional, Takeuchi, H., additional, Shimaki, Y., additional, Shirai, K., additional, Iijima, Y., additional, Tsuda, Y., additional, Watanabe, S., additional, and Yoshikawa, M., additional

Published
2020
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9. Sample collection from asteroid (162173) Ryugu by Hayabusa2: Implications for surface evolution

Author

Morota, T., primary, Sugita, S., additional, Cho, Y., additional, Kanamaru, M., additional, Tatsumi, E., additional, Sakatani, N., additional, Honda, R., additional, Hirata, N., additional, Kikuchi, H., additional, Yamada, M., additional, Yokota, Y., additional, Kameda, S., additional, Matsuoka, M., additional, Sawada, H., additional, Honda, C., additional, Kouyama, T., additional, Ogawa, K., additional, Suzuki, H., additional, Yoshioka, K., additional, Hayakawa, M., additional, Hirabayashi, M., additional, Miyamoto, H., additional, Michikami, T., additional, Hiroi, T., additional, Hemmi, R., additional, Barnouin, O. S., additional, Ernst, C. M., additional, Kitazato, K., additional, Nakamura, T., additional, Riu, L., additional, Senshu, H., additional, Kobayashi, H., additional, Sasaki, S., additional, Komatsu, G., additional, Tanabe, N., additional, Fujii, Y., additional, Irie, T., additional, Suemitsu, M., additional, Takaki, N., additional, Sugimoto, C., additional, Yumoto, K., additional, Ishida, M., additional, Kato, H., additional, Moroi, K., additional, Domingue, D., additional, Michel, P., additional, Pilorget, C., additional, Iwata, T., additional, Abe, M., additional, Ohtake, M., additional, Nakauchi, Y., additional, Tsumura, K., additional, Yabuta, H., additional, Ishihara, Y., additional, Noguchi, R., additional, Matsumoto, K., additional, Miura, A., additional, Namiki, N., additional, Tachibana, S., additional, Arakawa, M., additional, Ikeda, H., additional, Wada, K., additional, Mizuno, T., additional, Hirose, C., additional, Hosoda, S., additional, Mori, O., additional, Shimada, T., additional, Soldini, S., additional, Tsukizaki, R., additional, Yano, H., additional, Ozaki, M., additional, Takeuchi, H., additional, Yamamoto, Y., additional, Okada, T., additional, Shimaki, Y., additional, Shirai, K., additional, Iijima, Y., additional, Noda, H., additional, Kikuchi, S., additional, Yamaguchi, T., additional, Ogawa, N., additional, Ono, G., additional, Mimasu, Y., additional, Yoshikawa, K., additional, Takahashi, T., additional, Takei, Y., additional, Fujii, A., additional, Nakazawa, S., additional, Terui, F., additional, Tanaka, S., additional, Yoshikawa, M., additional, Saiki, T., additional, Watanabe, S., additional, and Tsuda, Y., additional

Published
2020
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10. Ryugu's Parent-Body Processes Estimated from Hayabusa2 Multi-Band Optical Observations

Author

Sugita, S., Honda, R., Morota, T., Kameda, S., Sawada, H., Tatsumi, E., Honda, C., Yokota, Y., Yamada, M., Kouyama, T., Sakatani, N., Suzuki, H., Yoshioka, K., Hayakawa, M., Cho, Y., Matsuoka, M., Hirata, N., Domingue, D. L., Miyamoto, H., Kikuchi, H., Hemmi, R., Michikami, T., Barnouin, O.S., Ernst, C. M., Palmer, E., Gaskell, R., Michel, P., Hirabayashi, M., Jaumann, R, Otto, K., Schroeder, S., Hiroi, T., Nakamura, T., Komatsu, G., Yoshikawa, M., Tanaka, S., Shirai, K., Watanabe, S, Tsuda, Y., Schmitz, N., and Ogawa, K.

Subjects
Planetengeologie, Asteroiden und Kometen, surface boulders, Ryugu, meteorites, Hayabusa2
Published
2019

11. Spatial Distribution an Morphology of Craters on Ryugu: Implications for Surface Processes on the C-Type Asteroid

Author

Cho, Y., Morota, T., Kanamaru, M., Ernst, C. M., Barnouin, Olivier S., Tatsumi, E., Hirabayashi, M., Otto, Katharina A., Schmitz, Nicole, Wagner, Roland, Jaumann, Ralf, Miyamoto, H., Kikuchi, H., Hemmi, R., Honda, R., Kameda, S., Yokota, Y., Kouyama, Toru, Suzuki, H., Yamada, M., Sakatani, N., Honda, C., Hayakawa, M., Yoshioka, K., Matsuoka, Moe, Michikami, T., Hirata, N., Sawada, H., and Sugita, Seiji

Subjects
Planetengeologie, Asteroiden und Kometen, Craters, asteroid, morphology, Ryugu, surface processes, Hayabusa2, ONC
Published
2019

12. The Evolution of Ryugu's Parent Body Constrained by Hayabusa2 Imaging Observations

Author

Sugita, S., Honda, R., Kameda, S., Honda, C., Yokota, Y., Yamada, M., Kouyama, T., Sakatani, N., Suzuki, H., Yoshioka, K., Cho, Y., Matsuoka, M., Ogawa, K., Domingue, D.L., Miyamoto, H., Barnouin, O.S., Michel, P., Ernst, C. M., Hiroi, T., Nakamura, T., Sawada, H., Hayakawa, M., Hirata, N., Kikuchi, H., Hemmi, R., Michikami, T., Palmer, E., Gaskell, R., Hirabayashi, M., Jaumann, R, Otto, K., Schmitz, N., Schröder, S.E., Komatsu, G., Tanaka, S., Shirai, K., Yoshikawa, M., Watanabe, S, and Tsuda, Y.

Subjects
Planetengeologie, Asteroiden und Kometen, Ryugu, Hayabusa2
Published
2019

13. High Porosity Nature of the Top-Shape C-Type Asteroid 162173 Ryugu as Observed by Hayabusa2

Author

Watanabe, S, Hirabayashi, M., Hirata, N., Shimaki, Y., Ikeda, H., Tatsumi, E., Yoshikawa, M., Kikuchi, S., Yabuta, H., Nakamura, T., Tachibana, S., Ishihara, Y., Morota, T., Kitazato, K., Sakatani, N., Matsumoto, K., Wada, Koji, Senshu, H., Honda, C., Michikami, T., Takeuchi, H., Kouyama, T., Honda, R., Kameda, S., Fuse, T., Miyamoto, H., Komatsu, G., Sugita, S., Okada, T., Namiki, N., Arakawa, M., Ishiguro, M., Abe, M., Gaskell, R., Palmer, E., Barnouin, O.S., Michel, P., French, A. S.V, McMahon, J. W., Scheeres, D. J., Abell, P. A., Yamamoto, Y., Tanaka, S., Shirai, K., Matsuoka, M., Yamada, M., Yokota, Y., Suzuki, H., Yoshioka, K., Cho, Y., Nishikawa, N., Sugiyama, T., Kikuchi, H., Hemmi, R., Yamaguchi, T., Ogawa, N., Ono, G., Mimasu, Y., Yoshikawa, K., Takahashi, T., Takei, Y., Fujii, A., Hirose, C., Iwata, T., Hayakawa, M., Hosoda, S., Mori, O., Sawada, H., Shimada, T., Soldini, S., Yano, H., Tsukizaki, R., Ozaki, H., Iijima, Y., Ogawa, K., Fujimoto, M., Ho, T.-M., Moussi-Soffys, A., Jaumann, R, Bibring, J-.P., Krause, Christian, Terui, F., Saiki, T., Nakazawa, S., and Tsuda, Y.

Subjects
Planetengeologie, Asteroid, Systementwicklung und Projektbüro, Ryugu, Nutzerzentrum für Weltraumexperimente (MUSC), Hayabusa2
Published
2019

14. The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

Author

Sugita, S., primary, Honda, R., additional, Morota, T., additional, Kameda, S., additional, Sawada, H., additional, Tatsumi, E., additional, Yamada, M., additional, Honda, C., additional, Yokota, Y., additional, Kouyama, T., additional, Sakatani, N., additional, Ogawa, K., additional, Suzuki, H., additional, Okada, T., additional, Namiki, N., additional, Tanaka, S., additional, Iijima, Y., additional, Yoshioka, K., additional, Hayakawa, M., additional, Cho, Y., additional, Matsuoka, M., additional, Hirata, N., additional, Miyamoto, H., additional, Domingue, D., additional, Hirabayashi, M., additional, Nakamura, T., additional, Hiroi, T., additional, Michikami, T., additional, Michel, P., additional, Ballouz, R.-L., additional, Barnouin, O. S., additional, Ernst, C. M., additional, Schröder, S. E., additional, Kikuchi, H., additional, Hemmi, R., additional, Komatsu, G., additional, Fukuhara, T., additional, Taguchi, M., additional, Arai, T., additional, Senshu, H., additional, Demura, H., additional, Ogawa, Y., additional, Shimaki, Y., additional, Sekiguchi, T., additional, Müller, T. G., additional, Hagermann, A., additional, Mizuno, T., additional, Noda, H., additional, Matsumoto, K., additional, Yamada, R., additional, Ishihara, Y., additional, Ikeda, H., additional, Araki, H., additional, Yamamoto, K., additional, Abe, S., additional, Yoshida, F., additional, Higuchi, A., additional, Sasaki, S., additional, Oshigami, S., additional, Tsuruta, S., additional, Asari, K., additional, Tazawa, S., additional, Shizugami, M., additional, Kimura, J., additional, Otsubo, T., additional, Yabuta, H., additional, Hasegawa, S., additional, Ishiguro, M., additional, Tachibana, S., additional, Palmer, E., additional, Gaskell, R., additional, Le Corre, L., additional, Jaumann, R., additional, Otto, K., additional, Schmitz, N., additional, Abell, P. A., additional, Barucci, M. A., additional, Zolensky, M. E., additional, Vilas, F., additional, Thuillet, F., additional, Sugimoto, C., additional, Takaki, N., additional, Suzuki, Y., additional, Kamiyoshihara, H., additional, Okada, M., additional, Nagata, K., additional, Fujimoto, M., additional, Yoshikawa, M., additional, Yamamoto, Y., additional, Shirai, K., additional, Noguchi, R., additional, Ogawa, N., additional, Terui, F., additional, Kikuchi, S., additional, Yamaguchi, T., additional, Oki, Y., additional, Takao, Y., additional, Takeuchi, H., additional, Ono, G., additional, Mimasu, Y., additional, Yoshikawa, K., additional, Takahashi, T., additional, Takei, Y., additional, Fujii, A., additional, Hirose, C., additional, Nakazawa, S., additional, Hosoda, S., additional, Mori, O., additional, Shimada, T., additional, Soldini, S., additional, Iwata, T., additional, Abe, M., additional, Yano, H., additional, Tsukizaki, R., additional, Ozaki, M., additional, Nishiyama, K., additional, Saiki, T., additional, Watanabe, S., additional, and Tsuda, Y., additional

Published
2019
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15. Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu—A spinning top–shaped rubble pile

Author

Watanabe, S., primary, Hirabayashi, M., additional, Hirata, N., additional, Hirata, Na., additional, Noguchi, R., additional, Shimaki, Y., additional, Ikeda, H., additional, Tatsumi, E., additional, Yoshikawa, M., additional, Kikuchi, S., additional, Yabuta, H., additional, Nakamura, T., additional, Tachibana, S., additional, Ishihara, Y., additional, Morota, T., additional, Kitazato, K., additional, Sakatani, N., additional, Matsumoto, K., additional, Wada, K., additional, Senshu, H., additional, Honda, C., additional, Michikami, T., additional, Takeuchi, H., additional, Kouyama, T., additional, Honda, R., additional, Kameda, S., additional, Fuse, T., additional, Miyamoto, H., additional, Komatsu, G., additional, Sugita, S., additional, Okada, T., additional, Namiki, N., additional, Arakawa, M., additional, Ishiguro, M., additional, Abe, M., additional, Gaskell, R., additional, Palmer, E., additional, Barnouin, O. S., additional, Michel, P., additional, French, A. S., additional, McMahon, J. W., additional, Scheeres, D. J., additional, Abell, P. A., additional, Yamamoto, Y., additional, Tanaka, S., additional, Shirai, K., additional, Matsuoka, M., additional, Yamada, M., additional, Yokota, Y., additional, Suzuki, H., additional, Yoshioka, K., additional, Cho, Y., additional, Nishikawa, N., additional, Sugiyama, T., additional, Kikuchi, H., additional, Hemmi, R., additional, Yamaguchi, T., additional, Ogawa, N., additional, Ono, G., additional, Mimasu, Y., additional, Yoshikawa, K., additional, Takahashi, T., additional, Takei, Y., additional, Fujii, A., additional, Hirose, C., additional, Iwata, T., additional, Hayakawa, M., additional, Hosoda, S., additional, Mori, O., additional, Sawada, H., additional, Shimada, T., additional, Soldini, S., additional, Yano, H., additional, Tsukizaki, R., additional, Ozaki, M., additional, Iijima, Y., additional, Ogawa, K., additional, Fujimoto, M., additional, Ho, T.-M., additional, Moussi, A., additional, Jaumann, R., additional, Bibring, J.-P., additional, Krause, C., additional, Terui, F., additional, Saiki, T., additional, Nakazawa, S., additional, and Tsuda, Y., additional

Published
2019
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16. Impact cratering experiments in brittle targets with variable thickness: Implications for deep pit craters on Mars

Author

Hagermann, A., Lykawka, P. S., Michikami, T., Miyamoto, H., Miura, S., and Haruyama, Junichi

Subjects
Martian, geography, geography.geographical_feature_category, Projectile, Laboratoryexperiments, Laboratory experiments, Pit crater, Astronomy and Astrophysics, Mars Exploration Program, Impact cratering process, Subsurface cavity, Lava tube, Penetration regime, Brittleness, Impact crater, Space and Planetary Science, Petrology, Ejecta, Impact crateringprocess, Geology
Abstract

Accepted: 2014-03-12, 資料番号: SA1004679000

Published
2014

18. Detection of Intact Lava Tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder

Author

Kaku, T., primary, Haruyama, J., additional, Miyake, W., additional, Kumamoto, A., additional, Ishiyama, K., additional, Nishibori, T., additional, Yamamoto, K., additional, Crites, Sarah T., additional, Michikami, T., additional, Yokota, Y., additional, Sood, R., additional, Melosh, H. J., additional, Chappaz, L., additional, and Howell, K. C., additional

Published
2017
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19. CRACKS OF BOULDERS ON RYUGU: POSSIBILITY OF THERMALLY INDUCED ORIGIN.

Author

Sasaki, S., Kanda, S., Kikuchi, H., Michikami, T., Morota, T., Honda, C., Miyamoto, H., Henmi, R., Sugita, S., Tatsumi, E., Kanamaru, M., Sakatani, N., Watanabe, S., Namiki, N., Michel, P., Hirabayashi, M., Hirata, N., Nakamura, T., Noguchi, T., and Hiroi, T.

Subjects
BOULDERS, ROCK deformation, FRACTURE mechanics, THERMAL fatigue
Published
2021

21. THE SHAPE DISTRIBUTION OF SMALL BOULDERS ON ASTEROID RYUGU.

Author

Michikami, T., Hagermann, A., Morota, T., Okamura, H., Nomura, K., Miyamoto, H., Hirabayashi, M., Eri Tatsumi, Hirata, N., Noguchi, T., Cho, Y., Kameda, S., Kouyama, T., Yokota, Y., Noguchi, R., Hayakawa, M., Honda, R., Matsuoka, M., Sakatani, N., and Suzuki, H.

Subjects
BOULDERS, ASTEROIDS
Published
2021

24. Soluble organic molecules in samples of the carbonaceous asteroid (162173) Ryugu.

Author

Naraoka H, Takano Y, Dworkin JP, Oba Y, Hamase K, Furusho A, Ogawa NO, Hashiguchi M, Fukushima K, Aoki D, Schmitt-Kopplin P, Aponte JC, Parker ET, Glavin DP, McLain HL, Elsila JE, Graham HV, Eiler JM, Orthous-Daunay FR, Wolters C, Isa J, Vuitton V, Thissen R, Sakai S, Yoshimura T, Koga T, Ohkouchi N, Chikaraishi Y, Sugahara H, Mita H, Furukawa Y, Hertkorn N, Ruf A, Yurimoto H, Nakamura T, Noguchi T, Okazaki R, Yabuta H, Sakamoto K, Tachibana S, Connolly HC Jr, Lauretta DS, Abe M, Yada T, Nishimura M, Yogata K, Nakato A, Yoshitake M, Suzuki A, Miyazaki A, Furuya S, Hatakeda K, Soejima H, Hitomi Y, Kumagai K, Usui T, Hayashi T, Yamamoto D, Fukai R, Kitazato K, Sugita S, Namiki N, Arakawa M, Ikeda H, Ishiguro M, Hirata N, Wada K, Ishihara Y, Noguchi R, Morota T, Sakatani N, Matsumoto K, Senshu H, Honda R, Tatsumi E, Yokota Y, Honda C, Michikami T, Matsuoka M, Miura A, Noda H, Yamada T, Yoshihara K, Kawahara K, Ozaki M, Iijima YI, Yano H, Hayakawa M, Iwata T, Tsukizaki R, Sawada H, Hosoda S, Ogawa K, Okamoto C, Hirata N, Shirai K, Shimaki Y, Yamada M, Okada T, Yamamoto Y, Takeuchi H, Fujii A, Takei Y, Yoshikawa K, Mimasu Y, Ono G, Ogawa N, Kikuchi S, Nakazawa S, Terui F, Tanaka S, Saiki T, Yoshikawa M, Watanabe SI, and Tsuda Y

Abstract

The Hayabusa2 spacecraft collected samples from the surface of the carbonaceous near-Earth asteroid (162173) Ryugu and brought them to Earth. The samples were expected to contain organic molecules, which record processes that occurred in the early Solar System. We analyzed organic molecules extracted from the Ryugu surface samples. We identified a variety of molecules containing the atoms CHNOS, formed by methylation, hydration, hydroxylation, and sulfurization reactions. Amino acids, aliphatic amines, carboxylic acids, polycyclic aromatic hydrocarbons, and nitrogen-heterocyclic compounds were detected, which had properties consistent with an abiotic origin. These compounds likely arose from an aqueous reaction on Ryugu's parent body and are similar to the organics in Ivuna-type meteorites. These molecules can survive on the surfaces of asteroids and be transported throughout the Solar System.

Published
2023
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25. Noble gases and nitrogen in samples of asteroid Ryugu record its volatile sources and recent surface evolution.

Author

Okazaki R, Marty B, Busemann H, Hashizume K, Gilmour JD, Meshik A, Yada T, Kitajima F, Broadley MW, Byrne D, Füri E, Riebe MEI, Krietsch D, Maden C, Ishida A, Clay P, Crowther SA, Fawcett L, Lawton T, Pravdivtseva O, Miura YN, Park J, Bajo KI, Takano Y, Yamada K, Kawagucci S, Matsui Y, Yamamoto M, Righter K, Sakai S, Iwata N, Shirai N, Sekimoto S, Inagaki M, Ebihara M, Yokochi R, Nishiizumi K, Nagao K, Lee JI, Kano A, Caffee MW, Uemura R, Nakamura T, Naraoka H, Noguchi T, Yabuta H, Yurimoto H, Tachibana S, Sawada H, Sakamoto K, Abe M, Arakawa M, Fujii A, Hayakawa M, Hirata N, Hirata N, Honda R, Honda C, Hosoda S, Iijima YI, Ikeda H, Ishiguro M, Ishihara Y, Iwata T, Kawahara K, Kikuchi S, Kitazato K, Matsumoto K, Matsuoka M, Michikami T, Mimasu Y, Miura A, Morota T, Nakazawa S, Namiki N, Noda H, Noguchi R, Ogawa N, Ogawa K, Okada T, Okamoto C, Ono G, Ozaki M, Saiki T, Sakatani N, Senshu H, Shimaki Y, Shirai K, Sugita S, Takei Y, Takeuchi H, Tanaka S, Tatsumi E, Terui F, Tsukizaki R, Wada K, Yamada M, Yamada T, Yamamoto Y, Yano H, Yokota Y, Yoshihara K, Yoshikawa M, Yoshikawa K, Furuya S, Hatakeda K, Hayashi T, Hitomi Y, Kumagai K, Miyazaki A, Nakato A, Nishimura M, Soejima H, Iwamae A, Yamamoto D, Yogata K, Yoshitake M, Fukai R, Usui T, Connolly HC Jr, Lauretta D, Watanabe SI, and Tsuda Y

Abstract

The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have different abundances among the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating a ~5 million year exposure, and from implanted solar wind record the recent irradiation history of Ryugu after it migrated to its current orbit.

Published
2023
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26. Macromolecular organic matter in samples of the asteroid (162173) Ryugu.

Author

Yabuta H, Cody GD, Engrand C, Kebukawa Y, De Gregorio B, Bonal L, Remusat L, Stroud R, Quirico E, Nittler L, Hashiguchi M, Komatsu M, Okumura T, Mathurin J, Dartois E, Duprat J, Takahashi Y, Takeichi Y, Kilcoyne D, Yamashita S, Dazzi A, Deniset-Besseau A, Sandford S, Martins Z, Tamenori Y, Ohigashi T, Suga H, Wakabayashi D, Verdier-Paoletti M, Mostefaoui S, Montagnac G, Barosch J, Kamide K, Shigenaka M, Bejach L, Matsumoto M, Enokido Y, Noguchi T, Yurimoto H, Nakamura T, Okazaki R, Naraoka H, Sakamoto K, Connolly HC Jr, Lauretta DS, Abe M, Okada T, Yada T, Nishimura M, Yogata K, Nakato A, Yoshitake M, Iwamae A, Furuya S, Hatakeda K, Miyazaki A, Soejima H, Hitomi Y, Kumagai K, Usui T, Hayashi T, Yamamoto D, Fukai R, Sugita S, Kitazato K, Hirata N, Honda R, Morota T, Tatsumi E, Sakatani N, Namiki N, Matsumoto K, Noguchi R, Wada K, Senshu H, Ogawa K, Yokota Y, Ishihara Y, Shimaki Y, Yamada M, Honda C, Michikami T, Matsuoka M, Hirata N, Arakawa M, Okamoto C, Ishiguro M, Jaumann R, Bibring JP, Grott M, Schröder S, Otto K, Pilorget C, Schmitz N, Biele J, Ho TM, Moussi-Soffys A, Miura A, Noda H, Yamada T, Yoshihara K, Kawahara K, Ikeda H, Yamamoto Y, Shirai K, Kikuchi S, Ogawa N, Takeuchi H, Ono G, Mimasu Y, Yoshikawa K, Takei Y, Fujii A, Iijima YI, Nakazawa S, Hosoda S, Iwata T, Hayakawa M, Sawada H, Yano H, Tsukizaki R, Ozaki M, Terui F, Tanaka S, Fujimoto M, Yoshikawa M, Saiki T, Tachibana S, Watanabe SI, and Tsuda Y

Abstract

Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by the Hayabusa2 spacecraft. We investigated the macromolecular organic matter in Ryugu samples and found that it contains aromatic and aliphatic carbon, ketone, and carboxyl functional groups. The spectroscopic features of the organic matter are consistent with those in chemically primitive carbonaceous chondrite meteorites that experienced parent-body aqueous alteration (reactions with liquid water). The morphology of the organic carbon includes nanoglobules and diffuse carbon associated with phyllosilicate and carbonate minerals. Deuterium and/or nitrogen-15 enrichments indicate that the organic matter formed in a cold molecular cloud or the presolar nebula. The diversity of the organic matter indicates variable levels of aqueous alteration on Ryugu's parent body.

Published
2023
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27. Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites.

Author

Yokoyama T, Nagashima K, Nakai I, Young ED, Abe Y, Aléon J, Alexander CMO, Amari S, Amelin Y, Bajo KI, Bizzarro M, Bouvier A, Carlson RW, Chaussidon M, Choi BG, Dauphas N, Davis AM, Di Rocco T, Fujiya W, Fukai R, Gautam I, Haba MK, Hibiya Y, Hidaka H, Homma H, Hoppe P, Huss GR, Ichida K, Iizuka T, Ireland TR, Ishikawa A, Ito M, Itoh S, Kawasaki N, Kita NT, Kitajima K, Kleine T, Komatani S, Krot AN, Liu MC, Masuda Y, McKeegan KD, Morita M, Motomura K, Moynier F, Nguyen A, Nittler L, Onose M, Pack A, Park C, Piani L, Qin L, Russell SS, Sakamoto N, Schönbächler M, Tafla L, Tang H, Terada K, Terada Y, Usui T, Wada S, Wadhwa M, Walker RJ, Yamashita K, Yin QZ, Yoneda S, Yui H, Zhang AC, Connolly HC Jr, Lauretta DS, Nakamura T, Naraoka H, Noguchi T, Okazaki R, Sakamoto K, Yabuta H, Abe M, Arakawa M, Fujii A, Hayakawa M, Hirata N, Hirata N, Honda R, Honda C, Hosoda S, Iijima YI, Ikeda H, Ishiguro M, Ishihara Y, Iwata T, Kawahara K, Kikuchi S, Kitazato K, Matsumoto K, Matsuoka M, Michikami T, Mimasu Y, Miura A, Morota T, Nakazawa S, Namiki N, Noda H, Noguchi R, Ogawa N, Ogawa K, Okada T, Okamoto C, Ono G, Ozaki M, Saiki T, Sakatani N, Sawada H, Senshu H, Shimaki Y, Shirai K, Sugita S, Takei Y, Takeuchi H, Tanaka S, Tatsumi E, Terui F, Tsuda Y, Tsukizaki R, Wada K, Watanabe SI, Yamada M, Yamada T, Yamamoto Y, Yano H, Yokota Y, Yoshihara K, Yoshikawa M, Yoshikawa K, Furuya S, Hatakeda K, Hayashi T, Hitomi Y, Kumagai K, Miyazaki A, Nakato A, Nishimura M, Soejima H, Suzuki A, Yada T, Yamamoto D, Yogata K, Yoshitake M, Tachibana S, and Yurimoto H

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 measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of 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, about [Formula: see text] million (statistical) or [Formula: see text] million (systematic) years after the 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 that of the Sun's photosphere than other natural samples do.

Published
2023
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28. A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu.

Author

Noguchi T, Matsumoto T, Miyake A, Igami Y, Haruta M, Saito H, Hata S, Seto Y, Miyahara M, Tomioka N, Ishii HA, Bradley JP, Ohtaki KK, Dobrică E, Leroux H, Le Guillou C, Jacob D, de la Peña F, Laforet S, Marinova M, Langenhorst F, Harries D, Beck P, Phan THV, Rebois R, Abreu NM, Gray J, Zega T, Zanetta PM, Thompson MS, Stroud R, Burgess K, Cymes BA, Bridges JC, Hicks L, Lee MR, Daly L, Bland PA, Zolensky ME, Frank DR, Martinez J, Tsuchiyama A, Yasutake M, Matsuno J, Okumura S, Mitsukawa I, Uesugi K, Uesugi M, Takeuchi A, Sun M, Enju S, Takigawa A, Michikami T, Nakamura T, Matsumoto M, Nakauchi Y, Abe M, Arakawa M, Fujii A, Hayakawa M, Hirata N, Hirata N, Honda R, Honda C, Hosoda S, Iijima YI, Ikeda H, Ishiguro M, Ishihara Y, Iwata T, Kawahara K, Kikuchi S, Kitazato K, Matsumoto K, Matsuoka M, Mimasu Y, Miura A, Morota T, Nakazawa S, Namiki N, Noda H, Noguchi R, Ogawa N, Ogawa K, Okada T, Okamoto C, Ono G, Ozaki M, Saiki T, Sakatani N, Sawada H, Senshu H, Shimaki Y, Shirai K, Sugita S, Takei Y, Takeuchi H, Tanaka S, Tatsumi E, Terui F, Tsukizaki R, Wada K, Yamada M, Yamada T, Yamamoto Y, Yano H, Yokota Y, Yoshihara K, Yoshikawa M, Yoshikawa K, Fukai R, Furuya S, Hatakeda K, Hayashi T, Hitomi Y, Kumagai K, Miyazaki A, Nakato A, Nishimura M, Soejima H, Suzuki AI, Usui T, Yada T, Yamamoto D, Yogata K, Yoshitake M, Connolly HC Jr, Lauretta DS, Yurimoto H, Nagashima K, Kawasaki N, Sakamoto N, Okazaki R, Yabuta H, Naraoka H, Sakamoto K, Tachibana S, Watanabe SI, and Tsuda Y

Abstract

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe 3+ to Fe 2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (-OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2022.)

Published
2023
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29. First asteroid gas sample delivered by the Hayabusa2 mission: A treasure box from Ryugu.

Author

Okazaki R, Miura YN, Takano Y, Sawada H, Sakamoto K, Yada T, Yamada K, Kawagucci S, Matsui Y, Hashizume K, Ishida A, Broadley MW, Marty B, Byrne D, Füri E, Meshik A, Pravdivtseva O, Busemann H, Riebe MEI, Gilmour J, Park J, Bajo KI, Righter K, Sakai S, Sekimoto S, Kitajima F, Crowther SA, Iwata N, Shirai N, Ebihara M, Yokochi R, Nishiizumi K, Nagao K, Lee JI, Clay P, Kano A, Caffee MW, Uemura R, Inagaki M, Krietsch D, Maden C, Yamamoto M, Fawcett L, Lawton T, Nakamura T, Naraoka H, Noguchi T, Yabuta H, Yurimoto H, Tsuda Y, Watanabe SI, Abe M, Arakawa M, Fujii A, Hayakawa M, Hirata N, Hirata N, Honda R, Honda C, Hosoda S, Iijima YI, Ikeda H, Ishiguro M, Ishihara Y, Iwata T, Kawahara K, Kikuchi S, Kitazato K, Matsumoto K, Matsuoka M, Michikami T, Mimasu Y, Miura A, Morota T, Nakazawa S, Namiki N, Noda H, Noguchi R, Ogawa N, Ogawa K, Okada T, Okamoto C, Ono G, Ozaki M, Saiki T, Sakatani N, Senshu H, Shimaki Y, Shirai K, Sugita S, Takei Y, Takeuchi H, Tanaka S, Tatsumi E, Terui F, Tsukizaki R, Wada K, Yamada M, Yamada T, Yamamoto Y, Yano H, Yokota Y, Yoshihara K, Yoshikawa M, Yoshikawa K, Furuya S, Hatakeda K, Hayashi T, Hitomi Y, Kumagai K, Miyazaki A, Nakato A, Nishimura M, Soejima H, Iwamae A, Yamamoto D, Yogata K, Yoshitake M, Fukai R, Usui T, Ireland T, Connolly HC Jr, Lauretta DS, and Tachibana S

Abstract

The Hayabusa2 spacecraft returned to Earth from the asteroid 162173 Ryugu on 6 December 2020. One day after the recovery, the gas species retained in the sample container were extracted and measured on-site and stored in gas collection bottles. The container gas consists of helium and neon with an extraterrestrial 3 He/ 4 He and 20 Ne/ 22 Ne ratios, along with some contaminant terrestrial atmospheric gases. A mixture of solar and Earth's atmospheric gas is the best explanation for the container gas composition. Fragmentation of Ryugu grains within the sample container is discussed on the basis of the estimated amount of indigenous He and the size distribution of the recovered Ryugu grains. This is the first successful return of gas species from a near-Earth asteroid.

Published
2022
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30. On the origin and evolution of the asteroid Ryugu: A comprehensive geochemical perspective.

Author

Nakamura E, Kobayashi K, Tanaka R, Kunihiro T, Kitagawa H, Potiszil C, Ota T, Sakaguchi C, Yamanaka M, Ratnayake DM, Tripathi H, Kumar R, Avramescu ML, Tsuchida H, Yachi Y, Miura H, Abe M, Fukai R, Furuya S, Hatakeda K, Hayashi T, Hitomi Y, Kumagai K, Miyazaki A, Nakato A, Nishimura M, Okada T, Soejima H, Sugita S, Suzuki A, Usui T, Yada T, Yamamoto D, Yogata K, Yoshitake M, Arakawa M, Fujii A, Hayakawa M, Hirata N, Hirata N, Honda R, Honda C, Hosoda S, Iijima YI, Ikeda H, Ishiguro M, Ishihara Y, Iwata T, Kawahara K, Kikuchi S, Kitazato K, Matsumoto K, Matsuoka M, Michikami T, Mimasu Y, Miura A, Morota T, Nakazawa S, Namiki N, Noda H, Noguchi R, Ogawa N, Ogawa K, Okamoto C, Ono G, Ozaki M, Saiki T, Sakatani N, Sawada H, Senshu H, Shimaki Y, Shirai K, Takei Y, Takeuchi H, Tanaka S, Tatsumi E, Terui F, Tsukizaki R, Wada K, Yamada M, Yamada T, Yamamoto Y, Yano H, Yokota Y, Yoshihara K, Yoshikawa M, Yoshikawa K, Fujimoto M, Watanabe SI, and Tsuda Y

Subjects
Water, Meteoroids, Solar System
Abstract

Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ 18 O, Δ 17 O, and ε 54 Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10's of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation.

Published
2022
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31. Highly porous nature of a primitive asteroid revealed by thermal imaging.

Author

Okada T, Fukuhara T, Tanaka S, Taguchi M, Arai T, Senshu H, Sakatani N, Shimaki Y, Demura H, Ogawa Y, Suko K, Sekiguchi T, Kouyama T, Takita J, Matsunaga T, Imamura T, Wada T, Hasegawa S, Helbert J, Müller TG, Hagermann A, Biele J, Grott M, Hamm M, Delbo M, Hirata N, Hirata N, Yamamoto Y, Sugita S, Namiki N, Kitazato K, Arakawa M, Tachibana S, Ikeda H, Ishiguro M, Wada K, Honda C, Honda R, Ishihara Y, Matsumoto K, Matsuoka M, Michikami T, Miura A, Morota T, Noda H, Noguchi R, Ogawa K, Shirai K, Tatsumi E, Yabuta H, Yokota Y, Yamada M, Abe M, Hayakawa M, Iwata T, Ozaki M, Yano H, Hosoda S, Mori O, Sawada H, Shimada T, Takeuchi H, Tsukizaki R, Fujii A, Hirose C, Kikuchi S, Mimasu Y, Ogawa N, Ono G, Takahashi T, Takei Y, Yamaguchi T, Yoshikawa K, Terui F, Saiki T, Nakazawa S, Yoshikawa M, Watanabe S, and Tsuda Y

Abstract

Carbonaceous (C-type) asteroids 1 are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites 2,3 and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth's atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR) 4 onboard the spacecraft Hayabusa2 5 , indicating that the asteroid's boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m -2  s -0.5  K -1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites 6 and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect 7,8 . We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites 6 . These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity 9 of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies 10 .

Published
2020
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32. Three-dimensional structure of Hayabusa samples: origin and evolution of Itokawa regolith.

Author

Tsuchiyama A, Uesugi M, Matsushima T, Michikami T, Kadono T, Nakamura T, Uesugi K, Nakano T, Sandford SA, Noguchi R, Matsumoto T, Matsuno J, Nagano T, Imai Y, Takeuchi A, Suzuki Y, Ogami T, Katagiri J, Ebihara M, Ireland TR, Kitajima F, Nagao K, Naraoka H, Noguchi T, Okazaki R, Yurimoto H, Zolensky ME, Mukai T, Abe M, Yada T, Fujimura A, Yoshikawa M, and Kawaguchi J

Abstract

Regolith particles on the asteroid Itokawa were recovered by the Hayabusa mission. Their three-dimensional (3D) structure and other properties, revealed by x-ray microtomography, provide information on regolith formation. Modal abundances of minerals, bulk density (3.4 grams per cubic centimeter), and the 3D textures indicate that the particles represent a mixture of equilibrated and less-equilibrated LL chondrite materials. Evidence for melting was not seen on any of the particles. Some particles have rounded edges. Overall, the particles' size and shape are different from those seen in particles from the lunar regolith. These features suggest that meteoroid impacts on the asteroid surface primarily form much of the regolith particle, and that seismic-induced grain motion in the smooth terrain abrades them over time.

Published
2011
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33. Regolith migration and sorting on asteroid Itokawa.

Author

Miyamoto H, Yano H, Scheeres DJ, Abe S, Barnouin-Jha O, Cheng AF, Demura H, Gaskell RW, Hirata N, Ishiguro M, Michikami T, Nakamura AM, Nakamura R, Saito J, and Sasaki S

Abstract

High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum, microgravity environment. These processes likely include granular convection, landslide-like granular migrations, and particle sorting, resulting in the segregation of the fine gravels into areas of potential lows. Granular processes become major resurfacing processes because of Itokawa's small size, implying that they can occur on other small asteroids should those have regolith.

Published
2007
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