道上　達広（ミチカミ　タツヒロ）

工学部 機械工学科教授

Last Updated :2025/06/20

■教員コメント

コメント

小惑星探査機「はやぶさ」の画像データの解析、天体衝突を模擬した高速度衝突実験を行っています。最近は、イトカワ粒子の形状の研究や、月、火星の縦穴構造の実験的研究を行っています。

■研究者基本情報

学位

  • 博士（理学）（東京大学）

ホームページURL

科研費研究者番号

60369931

ORCID ID

0000-0003-3096-5789

J-Global ID

研究キーワード

  • 小惑星探査機はやぶさ   小惑星探査機はやぶさ2   小惑星イトカワ、リュウグウ   レゴリス   小惑星   惑星科学   

現在の研究分野（キーワード）

小惑星探査機「はやぶさ」の画像データの解析、天体衝突を模擬した高速度衝突実験を行っています。最近は、イトカワ粒子の形状の研究や、月、火星の縦穴構造の実験的研究を行っています。

研究分野

  • 自然科学一般 / 固体地球科学 / 惑星科学

■経歴

経歴

  • 2019年04月 - 現在  近畿大学工学部 教育推進センター教授
  • 2012年04月 - 2019年03月  近畿大学工学部 教育推進センター准教授
  • 2008年04月 - 2012年03月  福島工業高等専門学校一般教科 物理科准教授
  • 2003年04月 - 2008年03月  福島工業高等専門学校一般教科 物理科専任講師
  • 1997年04月 - 1998年03月  日本貨物鉄道株式会社（JR貨物）

学歴

  • 1998年04月 - 2001年07月   東京大学   理学系研究科   地球惑星科学専攻 博士課程
  • 1995年04月 - 1997年03月   北海道大学   理学研究科   地球惑星科学専攻 修士課程
  • 1992年10月 - 1995年03月   北海道大学   理学部   地球物理学科
  • 1991年04月 - 1992年09月   北海道大学   理I系

委員歴

  • 2020-2022年 日本惑星科学会 最優秀発表賞／最優秀研究者賞 選考委員
  • 2016年 日本惑星科学会 秋季講演会 実行委員
  • 2005年 日本惑星科学会 秋季講演会 実行委員

■研究活動情報

受賞

  • 2010年12月 小惑星探査機「はやぶさ」功労者感謝状 宇宙開発担当大臣
  • 2010年12月 小惑星探査機「はやぶさ」功労者感謝状 文部科学大臣
  • 国際天文学連合から 小惑星 23169 Michikami 命名

論文

  • Tatsuhiro Michikami; Axel Hagermann
    Icarus 441 116693 - 116693 2025年11月 [査読有り]
  • Akira Tsuchiyama; Hirotaka Yamaguchi; Motohiro Ogawa; Akiko M. Nakamura; Tatsuhiro Michikami; Kentaro Uesugi
    Icarus 429 116432 - 116432 2025年03月 [査読有り]
  • Masaaki Miyahara; Takaaki Noguchi; Toru Matsumoto; Naotaka Tomioka; Akira Miyake; Yohei Igami; Yusuke Seto; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Bahae‐Eddine Mouloud; Maya Marinova; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Satoru Nakazawa; Tatsuaki Okada; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Makoto Yoshikawa; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Tomohiro Usui; Toru Yada; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamotoa; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei‐ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 59 12 3181 - 3192 2024年09月 [査読有り]
     
    Abstract The surface morphology of regolith grains from the C‐type asteroid Ryugu was studied in search of evidence of impact events on the asteroid. Scanning electron microscopy revealed that ~8% of C0105‐042 Ryugu grains have a smooth surface on one side of the grains. One of these grains has striated linear grooves (striations) on its smooth surface. Transmission electron microscopy of the grain showed that a porous fine‐grained Mg‐Fe phyllosilicate assemblage, which is the main component of Ryugu grains, is compacted near the smooth surface. The smooth surface with striations closely resembles a slickenside, a characteristic texture found in terrestrial fault rocks formed by shear deformation. There is no evidence of melting/decomposition in the Mg‐Fe phyllosilicates near the smooth surface, indicating that the shear heating temperature is less than ~1100 K. Assuming that the average length of the striations corresponds to the minimum displacement of the micro‐fault, the shock pressure recorded in the C0105‐042 Ryugu grain is estimated to be <~4.5 GPa by a fault mechanics calculation. The shock pressures of C0105‐042, together with those of C0014 (~2 GPa) and C0055 (>~3.9 GPa) in previous studies suggest that the impact velocities recorded in these grains are < ~0.89–1.63 km s−1. Based on the impact velocities, these grains may record an impact event that occurred when asteroid Ryugu was in the orbit in Main Belt.
  • Akira Tsuchiyama; Megumi Matsumoto; Junya Matsuno; Masahiro Yasutake; Tomoki Nakamura; Takaaki Noguchi; Akira Miyake; Kentaro Uesugi; Akihisa Takeuchi; Shota Okumura; Yuri Fujioka; Mingqi Sun; Aki Takigawa; Toru Matsumoto; Satomi Enju; Itaru Mitsukawa; Yuma Enokido; Tatsuhiko Kawamoto; Takeshi Mikouchi; Tatsuhiro Michikami; Tomoyo Morita; Mizuha Kikuiri; Kana Amano; Eiichi Kagawa; Stefano Rubino; Zelia Dionnet; Alice Aléon-Toppani; Rosario Brunetto; Michael E. Zolensky; Tsukasa Nakano; Naoto Nakano; Hisayoshi Yurimoto; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Toru Yada; Masahiro Nishimura; Aiko Nakato; Akiko Miyazaki; Kasumi Yogata; Masanao Abe; Tatsuaki Okada; Tomohiro Usui; Makoto Yoshikawa; Takanao Saiki; Satoshi Tanaka; Satoru Nakazawa; Fuyuto Terui; Shogo Tachibana; Sei-ichiro Watanabe; Yuichi Tsuda
    Geochimica et Cosmochimica Acta 375 146 - 172 2024年06月 [査読有り]
  • Dennis Harries; Toru Matsumoto; Falko Langenhorst; Takaaki Noguchi; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hikaru Saito; Satoshi Hata; Aki Takigawa; Yusuke Nakauchi; Shogo Tachibana; Tomoki Nakamura; Megumi Matsumoto; Hope A. Ishii; John P. Bradley; Kenta Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Bahae‐eddine Mouloud; Maya Marinova; Pierre Beck; Van T. H. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Tatsuhiro Michikami; Hisayoshi Yurimoto; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Toru Yada; Masahiro Nishimura; Aiko Nakato; Akiko Miyazaki; Kasumi Yogata; Masanao Abe; Tatsuaki Okada; Tomohiro Usui; Makoto Yoshikawa; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Satoru Nakazawa; Sei‐ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 59 8 2134 - 2148 2024年05月 [査読有り]
     
    Abstract Regolith samples returned from asteroid 162173 Ryugu by the Hayabusa2 mission provide direct means to study how space weathering operates on the surfaces of hydrous asteroids. The mechanisms of space weathering, its effects on mineral surfaces, and the characteristic time scales on which alteration occurs are central to understanding the spectroscopic properties and the taxonomy of asteroids in the solar system. Here, we investigate the behavior of the iron monosulfides mineral pyrrhotite (Fe1−xS) at the earliest stages of space weathering. Using electron microscopy methods, we identified a partially exposed pyrrhotite crystal that morphologically shows evidence for mass loss due to exposure to solar wind ion irradiation. We find that crystallographic changes to the pyrrhotite can be related to sulfur loss from its space‐exposed surface and the diffusive redistribution of resulting excess iron into the interior of the crystal. Diffusion profiles allow us to estimate an order of magnitude of the exposure time of a few thousand years consistent with previous estimates of space exposure. During this interval, the adjacent phyllosilicates did not acquire discernable damage, suggesting that they are less susceptible to alteration by ion irradiation than pyrrhotite.
  • Tatsuhiro Michikami; Axel Hagermann; Akira Tsuchiyama; Yushi Otsuka; Michihiko Nakamura; Satoshi Okumura; Harumasa Kano; Junya Matsuno; Sunao Hasegawa
    Icarus 116068 - 116068 2024年04月 [査読有り]
  • Rhonda M. Stroud; Jens Barosch; Lydie Bonal; Katherine Burgess; George D. Cody; Bradley T. De Gregorio; Luke Daly; Emmanuel Dartois; Elena Dobrică; Jean Duprat; Cecile Engrand; Dennis Harries; Minako Hashiguchi; Hope Ishii; Yoko Kebukawa; A. David Kilcoyne; Falko Langenhorst; Martin R. Lee; Larry R. Nittler; Eric Quirico; Taiga Okumura; Laurent Remusat; Scott Sandford; Hikaru Yabuta; Masanao Abe; Neyda M. Abreu; Paul A. J. Bagot; Pierre Beck; Laure Bejach; Phil A. Bland; John C. Bridges; Brittany A. Cymes; Alexandre Dazzi; Francisco de la Peña; Ariane Deniset‐Besseau; Satomi Enju; Yuma Enokido; David R. Frank; Jennifer Gray; Mitsutaka Haruta; Satoshi Hata; Leon Hicks; Yohei Igami; Damien Jacob; Kanami Kamide; Mutsumi Komatsu; Sylvain Laforet; Hugues Leroux; Corentin Le Guillou; Zita Martins; Maya Marinova; James Martinez; Jérémie Mathurin; Megumi Matsumoto; Toru Matsumoto; Junya Matsuno; Samuel McFadzean; Tatsuhiro Michikami; Itaru Mitsukawa; Akira Miyake; Masaaki Miyahara; Akiko Miyazaki; Gilles Montagnac; Smail Mostefaoui; Tomoki Nakamura; Aiko Nakato; Hiroshi Naraoka; Yusuke Nakauchi; Satoru Nakazawa; Masahiro Nishimura; Takaaki Noguchi; Kenta Ohtaki; Takuji Ohigashi; Tatsuaki Okada; Shota Okumura; Ryuji Okazaki; Thi H. V. Phan; Rolando Rebois; Kanako Sakamoto; Takanao Saiki; Hikaru Saito; Yusuke Seto; Miho Shigenaka; William Smith; Hiroki Suga; Mingqi Sun; Shogo Tachibana; Yoshio Takahashi; Yasuo Takeichi; Akihisa Takeuchi; Aki Takigawa; Yusuke Tamenori; Satoshi Tanaka; Fuyuto Terui; Michelle S. Thompson; Naotaka Tomioka; Akira Tsuchiyama; Yuichi Tsuda; Kentaro Uesugi; Masayuki Uesugi; Tomohiro Usui; Maximilien Verdier‐Paoletti; Daisuke Wakabayashi; Sei‐ichiro Watanabe; Toru Yada; Shohei Yamashita; Masahiro Yasutake; Kasumi Yogata; Makoto Yoshikawa; Hisayoshi Yurimoto; Pierre‐M. Zanetta; Thomas Zega; Michael E. Zolensky
    Meteoritics & Planetary Science 2024年01月 [査読有り]
     
    Abstract Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range of morphologies, elemental compositions, and carbon functional chemistries consistent with those of carbonaceous chondrites that have experienced low‐temperature aqueous alteration. Both nanoglobules and diffuse organic matter are abundant. Non‐globular organic particles are also present, and including some that contain nanodiamond clusters. Diffuse organic matter is finely distributed in and around phyllosilicates, forms coatings on other minerals, and is also preserved in vesicles in secondary minerals such as carbonate and pyrrhotite. The average elemental compositions determined by energy‐dispersive spectroscopy of extracted, demineralized insoluble organic matter samples A0107 and C0106 are C100N3O9S1 and C100N3O7S1, respectively, with the difference in O/C slightly outside the difference in the standard error of the mean. The functional chemistry of the nanoglobules varies from mostly aromatic C=C to mixtures of aromatic C=C, ketone C=O, aliphatic (CHn), and carboxyl (COOH) groups. Diffuse organic matter associated with phyllosilicates has variable aromatic C, ketone and carboxyl groups, and some localized aliphatics, but is dominated by molecular carbonate (CO3) absorption, comparable to prior observations of clay‐bound organic matter in CI meteorites.
  • Van T. H. Phan; Pierre Beck; Rolando Rebois; Eric Quirico; Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Maya Marinova; Falko Langenhorst; Dennis Harries; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Jérémie Mathurin; Alexandre Dazzi; Emmanuel Dartois; Cécile Engrand; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Satoru Nakazawa; Tatsuaki Okada; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Makoto Yoshikawa; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Tomohiro Usui; Toru Yada; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamotoa; Peter Hoppe; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei‐ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 2024年01月 [査読有り]
     
    Abstract The Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA) returned to the Earth samples of carbonaceous asteroid (162173) Ryugu. This mission offers a unique opportunity to investigate in the laboratory samples from a C‐type asteroid, without physical or chemical alteration by the terrestrial atmosphere. Here, we report on an investigation of the mineralogy and the organo‐chemistry of Hayabusa2 samples using a combination of micro‐ and nano‐infrared spectroscopy. Particles investigated with conventional FTIR spectroscopy have spectra dominated by phyllosilicate‐related absorption, as observed for samples of CI‐chondrites, selected ungrouped carbonaceous chondrites, and selected hydrated micrometeorites. Ryugu samples show smaller sulfate‐related absorption than CI‐chondrites. Our samples that were only briefly exposed to the Earth atmosphere show absorptions related to molecular water, revealing fast terrestrial contamination of the spectral signature at 3 μm. Overall, our FTIR data are in agreement with other work done on Ryugu samples, revealing a low degree of mineralogical variability across Ryugu samples. AFM‐IR mapping of the grains shows the presence of a micrometer‐sized organic globule in one of our analyzed grains. The AFM‐IR spectra obtained on this globule are similar to IR spectra obtained on IOM suggesting that it is constituted of refractory organic matter. This globule may host silicate in its interior, with a different mineralogy than bulk Ryugu phyllosilicate. The shape, presence of peculiar silicate, and the nature of organic constituting the globule point toward a pre‐accretionary origin of this globule and that at least part of Ryugu organics were inherited from the protosolar nebulae or the interstellar media. Altogether, our results show the similarities between Ryugu samples and CI chondrites.
  • Bahae‐eddine Mouloud; Damien Jacob; Francisco de la Peña; Maya Marinova; Corentin Le Guillou; Jean‐Christophe Viennet; Sylvain Laforet; Hugues Leroux; Adrien Teurtrie; Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrica; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Satoru Nakazawa; Tatsuaki Okada; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Makoto Yoshikawa; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Tomohiro Usui; Toru Yada; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamotoa; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei‐ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 2024年01月 [査読有り]
     
    Abstract Ryugu asteroid grains brought back to the Earth by the Hayabusa2 space mission are pristine samples containing hydrated minerals and organic compounds. Here, we investigate the mineralogy of their phyllosilicate‐rich matrix with four‐dimensional scanning transmission electron microscopy (4D‐STEM). We have identified and mapped the mineral phases at the nanometer scale (serpentine, smectite, pyrrhotite), observed the presence of Ni‐bearing pyrrhotite, and identified the serpentine polymorph as lizardite, in agreement with the reported aqueous alteration history of Ryugu. Furthermore, we have mapped the d‐spacings of smectite and observed a broad distribution of values, ranging from 1 to 2 nm, with an average d‐spacing of 1.24 nm, indicating significant heterogeneity within the sample. Such d‐spacing variability could be the result of either the presence of organic matter trapped in the interlayers or the influence of various geochemical conditions at the submicrometer scale, suggestive of a range of organic compounds and/or changes in smectite crystal chemistry.
  • Toru Matsumoto; Takaaki Noguchi; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hikaru Saito; Satoshi Hata; Dennis Harries; Aki Takigawa; Yusuke Nakauchi; Shogo Tachibana; Tomoki Nakamura; Megumi Matsumoto; Hope A. Ishii; John P. Bradley; Kenta Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Maya Marinova; Falko Langenhorst; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre-M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Tatsuhiro Michikami; Hisayoshi Yurimoto; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Toru Yada; Masahiro Nishimura; Aiko Nakato; Akiko Miyazaki; Kasumi Yogata; Masanao Abe; Tatsuaki Okada; Tomohiro Usui; Makoto Yoshikawa; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Satoru Nakazawa; Sei-ichiro Watanabe; Yuichi Tsuda
    Nature Astronomy 8 2 207 - 215 2023年11月 [査読有り]
     
    Abstract Large amounts of nitrogen compounds, such as ammonium salts, may be stored in icy bodies and comets, but the transport of these nitrogen-bearing solids into the near-Earth region is not well understood. Here, we report the discovery of iron nitride on magnetite grains from the surface of the near-Earth C-type carbonaceous asteroid Ryugu, suggesting inorganic nitrogen fixation. Micrometeoroid impacts and solar wind irradiation may have caused the selective loss of volatile species from major iron-bearing minerals to form the metallic iron. Iron nitride is a product of nitridation of the iron metal by impacts of micrometeoroids that have higher nitrogen contents than the CI chondrites. The impactors are probably primitive materials with origins in the nitrogen-rich reservoirs in the outer Solar System. Our observation implies that the amount of nitrogen available for planetary formation and prebiotic reactions in the inner Solar System is greater than previously recognized.
  • Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Bahae‐Eddine Mouloud; Maya Marinova; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; William A. Smith; Sam McFadzean; Pierre‐Etienne Martin; Paul A. J. Bagot; Dennis Fougerouse; David W. Saxey; Steven Reddy; William D. A. Rickard; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Satoru Nakazawa; Tatsuaki Okada; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Makoto Yoshikawa; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Tomohiro Usui; Toru Yada; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamotoa; Peter Hoppe; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei‐ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 2023年11月 [査読有り]
     
    Abstract Samples returned from the carbonaceous asteroid (162173) Ryugu by the Hayabusa2 mission revealed that Ryugu is composed of materials consistent with CI chondrites and some types of space weathering. We report detailed mineralogy of the fine‐grained Ryugu samples allocated to our “Sand” team and report additional space weathering features found on the grains. The dominant mineralogy is composed of a fine‐grained mixture of Mg‐rich saponite and serpentine, magnetite, pyrrhotite, pentlandite, dolomite, and Fe‐bearing magnesite. These grains have mineralogy comparable to that of CI chondrites, showing severe aqueous alteration but lacking ferrihydrite and sulfate. These results are similar to previous works on large Ryugu grains. In addition to the major minerals, we also find many minerals that are rare or have not been reported among CI chondrites. Accessory minerals identified are hydroxyapatite, Mg‐Na phosphate, olivine, low‐Ca pyroxene, Mg‐Al spinel, chromite, manganochromite, eskolaite, ilmenite, cubanite, polydymite, transjordanite, schreibersite, calcite, moissanite, and poorly crystalline phyllosilicate. We also show scanning transmission electron microscope and scanning electron microscope compositional maps and images of some space‐weathered grains and severely heated and melted grains. Although our mineralogical results are consistent with that of millimeter‐sized grains, the fine‐grained fraction is best suited to investigate impact‐induced space weathering.
  • Akiko Miyazaki; Toru Yada; Kasumi Yogata; Kentaro Hatakeda; Aiko Nakato; Masahiro Nishimura; Kana Nagashima; Kazuya Kumagai; Yuya Hitomi; Hiromichi Soejima; Rui Tahara; Rei Kanemaru; Arisa Nakano; Miwa Yoshitake; Ayako Iwamae; Shizuho Furuya; Akira Tsuchiyama; Shogo Tachibana; Tatsuhiro Michikami; Tatsuaki Okada; Masanao Abe; Tomohiro Usui
    Earth, Planets and Space 75 1 2023年11月 [査読有り]
     
    Abstract The bulk density of grains from a celestial body is a fundamental property related to its composition and structure, contributing to the understanding of its evolutionary history. In this study, we provide the bulk density of 637 grains returned from the C-type near-Earth asteroid 162173 Ryugu. This is the largest number of grains to date for the curation activity, corresponding to 38 wt.% of the total returned samples (approximately 5.4 g). Although several densities of the Ryugu grains were reported, the volume estimation of some samples showed uncertainties. Therefore, we applied a new volume estimation model calibrated by X-ray micro-computed tomography (XCT) to the Ryugu grains to more accurately estimate their bulk density. The obtained average bulk density of 637 Ryugu grains was 1.79 ± 0.31 g/cm3 (1σ variation) for weights of 0.5‒100 mg (sub-mm ‒to 10 mm) irrespective of their 3D shapes characterized by three axial length ratios, considered to be a representative of the returned samples. The bulk density distributions of the grains in Chambers A and C were statistically distinguishable, with mean values of 1.81 ± 0.30 and 1.76 ± 0.33 g/cm3 (1σ variations), respectively. Despite the small difference, bulk density may have differed by sampling site. The obtained average bulk density value of A + C samples was almost the same as that of 16 Ryugu grains estimated based on CT scanned data, and was consistent with the densities of CI chondrites (1.57–1.91 g/cm3). The axial ratios of the grains in Chambers A and C were similar and those of the 724 returned samples and the flying particles ejected during the sampling operations were also similar, suggesting that relatively small Ryugu materials (mm‒cm in size) are similar in shape. The minor difference between the Rygu grains and flying particles could be attributed to events such as scraping during sampling operations and transportation. Graphical Abstract
  • Hugues Leroux; Corentin Le Guillou; Maya Marinova; Sylvain Laforet; Jean‐Christophe Viennet; Bahae‐Eddine Mouloud; Adrien Teurtrie; Francisco de la Peña; Damien Jacob; Daniel Hallatt; Mario Pelaez Fernandez; David Troadec; Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrică; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre‐M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Satoru Nakazawa; Tatsuaki Okada; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Makoto Yoshikawa; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Tomohiro Usui; Toru Yada; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamotoa; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei‐Ichiro Watanabe; Yuichi Tsuda
    Meteoritics & Planetary Science 2023年11月 [査読有り]
     
    Abstract Samples were recently collected from the carbonaceous asteroid (162173) Ryugu, by the Japan Aerospace Exploration Agency (JAXA) Hayabusa2 mission. They resemble CI chondrites material, thus showing clear evidence of extensive aqueous alteration attested by the widespread presence of a mixture of serpentine and saponite. We present here a scanning transmission electron microscopy study of the Ryugu dominant lithology of the phyllosilicate matrix at the nanometer scale, which we compare with that of the Orgueil CI chondrite. In both objects, the phyllosilicates are of comparable nature and texture, consisting of a mixture of small‐sized crystallites of serpentine and saponite. At the micrometer scale or less, the texture is an alternation of fine and coarse domains. The fine‐grained regions are dominated by saponite. In Ryugu, they enclose numerous Fe,Ni nanosulfides, whereas in Orgueil, S‐ and Ni‐rich ferrihydrite is abundant. The coarse‐grained regions contain more serpentine and no or little Fe,Ni sulfides or ferrihydrite. Scanning transmission x‐ray microscopy at the Fe‐L3 edge also reveals that iron valency of phyllosilicates is higher and more homogeneous in Orgueil (~70% Fe3+) than in Ryugu (<50% Fe3+). We interpret the observed textures as being mostly a consequence of aqueous alteration, likely resulting from the replacement by phyllosilicates of submicrometric components, initially agglomerated by a primary accretion. The fine‐grained domains may result from the replacement of GEMS (GEMS—glass with embedded metal and sulfides) objects or from other types of nanometric assemblages of silicate and Fe‐based nanophases. On the other hand, the coarse‐grained regions may correspond to the replacement of anhydrous crystalline silicates of the olivine and pyroxene type. The major difference is the presence of Fe,Ni sulfides in Ryugu and of ferrihydrite and higher iron valency of phyllosilicates in Orgueil. This might be due to long‐term terrestrial weathering that would have destabilized the nanosulfides. We also explore an alternative scenario involving more oxidizing hydrothermal conditions on the Orgueil parent body.
  • Elena Dobrică; Hope A. Ishii; John P. Bradley; Kenta Ohtaki; Adrian J. Brearley; Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Maya Marinova; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H.V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre-M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Hisayoshi Yurimoto; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Toru Yada; Masahiro Nishimura; Aiko Nakato; Akiko Miyazaki; Kasumi Yogata; Masanao Abe; Tatsuaki Okada; Tomohiro Usui; Makoto Yoshikawa; Takanao Saiki; Satoshi Tanaka; Fuyuto Terui; Satoru Nakazawa; Sei-ichiro Watanabe; Yuichi Tsuda
    Geochimica et Cosmochimica Acta 346 65 - 75 2023年04月 [査読有り]
  • Tatsuhiro Michikami; Akira Tsuchiyama; Axel Hagermann; Akio Takeda; Katsuki Shishido; Yushi Otsuka; Osamu Sasaki; Michihiko Nakamura; Satoshi Okumura; Harumasa Kano; Sunao Hasegawa
    Icarus 392 115371 - 115371 2023年03月 [査読有り]
  • Hikaru Yabuta; George D. Cody; Cécile Engrand; Yoko Kebukawa; Bradley De Gregorio; Lydie Bonal; Laurent Remusat; Rhonda Stroud; Eric Quirico; Larry Nittler; Minako Hashiguchi; Mutsumi Komatsu; Taiga Okumura; Jérémie Mathurin; Emmanuel Dartois; Jean Duprat; Yoshio Takahashi; Yasuo Takeichi; David Kilcoyne; Shohei Yamashita; Alexandre Dazzi; Ariane Deniset-Besseau; Scott Sandford; Zita Martins; Yusuke Tamenori; Takuji Ohigashi; Hiroki Suga; Daisuke Wakabayashi; Maximilien Verdier-Paoletti; Smail Mostefaoui; Gilles Montagnac; Jens Barosch; Kanami Kamide; Miho Shigenaka; Laure Bejach; Megumi Matsumoto; Yuma Enokido; Takaaki Noguchi; Hisayoshi Yurimoto; Tomoki Nakamura; Ryuji Okazaki; Hiroshi Naraoka; Kanako Sakamoto; Harold C. Connolly; Dante S. Lauretta; Masanao Abe; Tatsuaki Okada; Toru Yada; Masahiro Nishimura; Kasumi Yogata; Aiko Nakato; Miwa Yoshitake; Ayako Iwamae; Shizuho Furuya; Kentaro Hatakeda; Akiko Miyazaki; Hiromichi Soejima; Yuya Hitomi; Kazuya Kumagai; Tomohiro Usui; Tasuku Hayashi; Daiki Yamamoto; Ryota Fukai; Seiji Sugita; Kohei Kitazato; Naru Hirata; Rie Honda; Tomokatsu Morota; Eri Tatsumi; Naoya Sakatani; Noriyuki Namiki; Koji Matsumoto; Rina Noguchi; Koji Wada; Hiroki Senshu; Kazunori Ogawa; Yasuhiro Yokota; Yoshiaki Ishihara; Yuri Shimaki; Manabu Yamada; Chikatoshi Honda; Tatsuhiro Michikami; Moe Matsuoka; Naoyuki Hirata; Masahiko Arakawa; Chisato Okamoto; Masateru Ishiguro; Ralf Jaumann; Jean-Pierre Bibring; Matthias Grott; Stefan Schröder; Katharina Otto; Cedric Pilorget; Nicole Schmitz; Jens Biele; Tra-Mi Ho; Aurélie Moussi-Soffys; Akira Miura; Hirotomo Noda; Tetsuya Yamada; Keisuke Yoshihara; Kosuke Kawahara; Hitoshi Ikeda; Yukio Yamamoto; Kei Shirai; Shota Kikuchi; Naoko Ogawa; Hiroshi Takeuchi; Go Ono; Yuya Mimasu; Kent Yoshikawa; Yuto Takei; Atsushi Fujii; Yu-ichi Iijima; Satoru Nakazawa; Satoshi Hosoda; Takahiro Iwata; Masahiko Hayakawa; Hirotaka Sawada; Hajime Yano; Ryudo Tsukizaki; Masanobu Ozaki; Fuyuto Terui; Satoshi Tanaka; Masaki Fujimoto; Makoto Yoshikawa; Takanao Saiki; Shogo Tachibana; Sei-ichiro Watanabe; Yuichi Tsuda
    Science 379 6634 2023年02月 [査読有り]
     
    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.
  • Hiroshi Naraoka; Yoshinori Takano; Jason P. Dworkin; Yasuhiro Oba; Kenji Hamase; Aogu Furusho; Nanako O. Ogawa; Minako Hashiguchi; Kazuhiko Fukushima; Dan Aoki; Philippe Schmitt-Kopplin; José C. Aponte; Eric T. Parker; Daniel P. Glavin; Hannah L. McLain; Jamie E. Elsila; Heather V. Graham; John M. Eiler; Francois-Regis Orthous-Daunay; Cédric Wolters; Junko Isa; Véronique Vuitton; Roland Thissen; Saburo Sakai; Toshihiro Yoshimura; Toshiki Koga; Naohiko Ohkouchi; Yoshito Chikaraishi; Haruna Sugahara; Hajime Mita; Yoshihiro Furukawa; Norbert Hertkorn; Alexander Ruf; Hisayoshi Yurimoto; Tomoki Nakamura; Takaaki Noguchi; Ryuji Okazaki; Hikaru Yabuta; Kanako Sakamoto; Shogo Tachibana; Harold C. Connolly; Dante S. Lauretta; Masanao Abe; Toru Yada; Masahiro Nishimura; Kasumi Yogata; Aiko Nakato; Miwa Yoshitake; Ayako Suzuki; Akiko Miyazaki; Shizuho Furuya; Kentaro Hatakeda; Hiromichi Soejima; Yuya Hitomi; Kazuya Kumagai; Tomohiro Usui; Tasuku Hayashi; Daiki Yamamoto; Ryota Fukai; Kohei Kitazato; Seiji Sugita; Noriyuki Namiki; Masahiko Arakawa; Hitoshi Ikeda; Masateru Ishiguro; Naru Hirata; Koji Wada; Yoshiaki Ishihara; Rina Noguchi; Tomokatsu Morota; Naoya Sakatani; Koji Matsumoto; Hiroki Senshu; Rie Honda; Eri Tatsumi; Yasuhiro Yokota; Chikatoshi Honda; Tatsuhiro Michikami; Moe Matsuoka; Akira Miura; Hirotomo Noda; Tetsuya Yamada; Keisuke Yoshihara; Kosuke Kawahara; Masanobu Ozaki; Yu-ichi Iijima; Hajime Yano; Masahiko Hayakawa; Takahiro Iwata; Ryudo Tsukizaki; Hirotaka Sawada; Satoshi Hosoda; Kazunori Ogawa; Chisato Okamoto; Naoyuki Hirata; Kei Shirai; Yuri Shimaki; Manabu Yamada; Tatsuaki Okada; Yukio Yamamoto; Hiroshi Takeuchi; Atsushi Fujii; Yuto Takei; Kento Yoshikawa; Yuya Mimasu; Go Ono; Naoko Ogawa; Shota Kikuchi; Satoru Nakazawa; Fuyuto Terui; Satoshi Tanaka; Takanao Saiki; Makoto Yoshikawa; Sei-ichiro Watanabe; Yuichi Tsuda
    Science 379 6634 2023年02月 [査読有り]
     
    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.
  • Sho SASAKI; Shiho KANDA; Hiroshi KIKUCHI; Tatsuhiro MICHIKAMI; Tomokatsu MOROTA; Chikatoshi HONDA; Hideaki MIYAMOTO; Ryodo HEMMI; Seiji SUGITA; Eri TATSUMI; Masanori KANAMARU; Sei-ichiro WATANABE; Noriyuki NAMIKI; Patrick MICHEL; Masatoshi HIRABAYASHI; Naru HIRATA; Tomoki NAKAMURA; Takaaki NOGUCHI; Takahiro HIROI; Naoya SAKATANI; Koji MATSUMOTO; Hirotomo NODA; Shingo KAMEDA; Tohru KOUYAMA; Hidehiko SUZUKI; Manabu YAMADA; Rie HONDA; Yuichiro CHO; Kazuo YOSHIOKA; Masahiko HAYAKAWA; Moe MATSUOKA; Rina NOGUCHI; Hirotaka SAWADA; Yasuhiro YOKOTA; Makoto YOSHIKAWA
    Journal of Evolving Space Activities 2023年
  • Takaaki Noguchi; Toru Matsumoto; Akira Miyake; Yohei Igami; Mitsutaka Haruta; Hikaru Saito; Satoshi Hata; Yusuke Seto; Masaaki Miyahara; Naotaka Tomioka; Hope A. Ishii; John P. Bradley; Kenta K. Ohtaki; Elena Dobrică; Hugues Leroux; Corentin Le Guillou; Damien Jacob; Francisco de la Peña; Sylvain Laforet; Maya Marinova; Falko Langenhorst; Dennis Harries; Pierre Beck; Thi H. V. Phan; Rolando Rebois; Neyda M. Abreu; Jennifer Gray; Thomas Zega; Pierre-M. Zanetta; Michelle S. Thompson; Rhonda Stroud; Kate Burgess; Brittany A. Cymes; John C. Bridges; Leon Hicks; Martin R. Lee; Luke Daly; Phil A. Bland; Michael E. Zolensky; David R. Frank; James Martinez; Akira Tsuchiyama; Masahiro Yasutake; Junya Matsuno; Shota Okumura; Itaru Mitsukawa; Kentaro Uesugi; Masayuki Uesugi; Akihisa Takeuchi; Mingqi Sun; Satomi Enju; Aki Takigawa; Tatsuhiro Michikami; Tomoki Nakamura; Megumi Matsumoto; Yusuke Nakauchi; Masanao Abe; Masahiko Arakawa; Atsushi Fujii; Masahiko Hayakawa; Naru Hirata; Naoyuki Hirata; Rie Honda; Chikatoshi Honda; Satoshi Hosoda; Yu-ichi Iijima; Hitoshi Ikeda; Masateru Ishiguro; Yoshiaki Ishihara; Takahiro Iwata; Kousuke Kawahara; Shota Kikuchi; Kohei Kitazato; Koji Matsumoto; Moe Matsuoka; Yuya Mimasu; Akira Miura; Tomokatsu Morota; Satoru Nakazawa; Noriyuki Namiki; Hirotomo Noda; Rina Noguchi; Naoko Ogawa; Kazunori Ogawa; Tatsuaki Okada; Chisato Okamoto; Go Ono; Masanobu Ozaki; Takanao Saiki; Naoya Sakatani; Hirotaka Sawada; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Seiji Sugita; Yuto Takei; Hiroshi Takeuchi; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Ryudo Tsukizaki; Koji Wada; Manabu Yamada; Tetsuya Yamada; Yukio Yamamoto; Hajime Yano; Yasuhiro Yokota; Keisuke Yoshihara; Makoto Yoshikawa; Kent Yoshikawa; Ryohta Fukai; Shizuho Furuya; Kentaro Hatakeda; Tasuku Hayashi; Yuya Hitomi; Kazuya Kumagai; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Hiromichi Soejima; Ayako I. Suzuki; Tomohiro Usui; Toru Yada; Daiki Yamamoto; Kasumi Yogata; Miwa Yoshitake; Harold C. Connolly; Dante S. Lauretta; Hisayoshi Yurimoto; Kazuhide Nagashima; Noriyuki Kawasaki; Naoya Sakamoto; Ryuji Okazaki; Hikaru Yabuta; Hiroshi Naraoka; Kanako Sakamoto; Shogo Tachibana; Sei-ichiro Watanabe; Yuichi Tsuda
    Nature Astronomy 2022年12月 [査読有り]
     
    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 Fe3+ to Fe2+ 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.
  • Ryuji Okazaki; Yayoi N. Miura; Yoshinori Takano; Hirotaka Sawada; Kanako Sakamoto; Toru Yada; Keita Yamada; Shinsuke Kawagucci; Yohei Matsui; Ko Hashizume; Akizumi Ishida; Michael W. Broadley; Bernard Marty; David Byrne; Evelyn Füri; Alex Meshik; Olga Pravdivtseva; Henner Busemann; My E.I. Riebe; Jamie Gilmour; Jisun Park; Ken-ichi Bajo; Kevin Righter; Saburo Sakai; Shun Sekimoto; Fumio Kitajima; Sarah A. Crowther; Naoyoshi Iwata; Naoki Shirai; Mitsuru Ebihara; Reika Yokochi; Kunihiko Nishiizumi; Keisuke Nagao; Jong Ik Lee; Patricia Clay; Akihiro Kano; Marc W. Caffee; Ryu Uemura; Makoto Inagaki; Daniela Krietsch; Colin Maden; Mizuki Yamamoto; Lydia Fawcett; Thomas Lawton; Tomoki Nakamura; Hiroshi Naraoka; Takaaki Noguchi; Hikaru Yabuta; Hisayoshi Yurimoto; Yuichi Tsuda; Sei-ichiro Watanabe; Masanao Abe; Masahiko Arakawa; Atsushi Fujii; Masahiko Hayakawa; Naoyuki Hirata; Naru Hirata; Rie Honda; Chikatoshi Honda; Satoshi Hosoda; Yu-ichi Iijima; Hitoshi Ikeda; Masateru Ishiguro; Yoshiaki Ishihara; Takahiro Iwata; Kosuke Kawahara; Shota Kikuchi; Kohei Kitazato; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Yuya Mimasu; Akira Miura; Tomokatsu Morota; Satoru Nakazawa; Noriyuki Namiki; Hirotomo Noda; Rina Noguchi; Naoko Ogawa; Kazunori Ogawa; Tatsuaki Okada; Chisato Okamoto; Go Ono; Masanobu Ozaki; Takanao Saiki; Naoya Sakatani; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Seiji Sugita; Yuto Takei; Hiroshi Takeuchi; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Ryudo Tsukizaki; Koji Wada; Manabu Yamada; Tetsuya Yamada; Yukio Yamamoto; Hajime Yano; Yasuhiro Yokota; Keisuke Yoshihara; Makoto Yoshikawa; Kent Yoshikawa; Shizuho Furuya; Kentaro Hatakeda; Tasuku Hayashi; Yuya Hitomi; Kazuya Kumagai; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Hiromichi Soejima; Ayako Iwamae; Daiki Yamamoto; Kasumi Yogata; Miwa Yoshitake; Ryota Fukai; Tomohiro Usui; Trevor Ireland; Harold C. Connolly; Dante S. Lauretta; Shogo Tachibana
    Science Advances 8 46 2022年11月 [査読有り]
     
    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.
  • Ryuji Okazaki; Bernard Marty; Henner Busemann; Ko Hashizume; Jamie D. Gilmour; Alex Meshik; Toru Yada; Fumio Kitajima; Michael W. Broadley; David Byrne; Evelyn Füri; My E. I. Riebe; Daniela Krietsch; Colin Maden; Akizumi Ishida; Patricia Clay; Sarah A. Crowther; Lydia Fawcett; Thomas Lawton; Olga Pravdivtseva; Yayoi N. Miura; Jisun Park; Ken-ichi Bajo; Yoshinori Takano; Keita Yamada; Shinsuke Kawagucci; Yohei Matsui; Mizuki Yamamoto; Kevin Righter; Saburo Sakai; Naoyoshi Iwata; Naoki Shirai; Shun Sekimoto; Makoto Inagaki; Mitsuru Ebihara; Reika Yokochi; Kunihiko Nishiizumi; Keisuke Nagao; Jong Ik Lee; Akihiro Kano; Marc W. Caffee; Ryu Uemura; Tomoki Nakamura; Hiroshi Naraoka; Takaaki Noguchi; Hikaru Yabuta; Hisayoshi Yurimoto; Shogo Tachibana; Hirotaka Sawada; Kanako Sakamoto; Masanao Abe; Masahiko Arakawa; Atsushi Fujii; Masahiko Hayakawa; Naoyuki Hirata; Naru Hirata; Rie Honda; Chikatoshi Honda; Satoshi Hosoda; Yu-ichi Iijima; Hitoshi Ikeda; Masateru Ishiguro; Yoshiaki Ishihara; Takahiro Iwata; Kosuke Kawahara; Shota Kikuchi; Kohei Kitazato; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Yuya Mimasu; Akira Miura; Tomokatsu Morota; Satoru Nakazawa; Noriyuki Namiki; Hirotomo Noda; Rina Noguchi; Naoko Ogawa; Kazunori Ogawa; Tatsuaki Okada; Chisato Okamoto; Go Ono; Masanobu Ozaki; Takanao Saiki; Naoya Sakatani; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Seiji Sugita; Yuto Takei; Hiroshi Takeuchi; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Ryudo Tsukizaki; Koji Wada; Manabu Yamada; Tetsuya Yamada; Yukio Yamamoto; Hajime Yano; Yasuhiro Yokota; Keisuke Yoshihara; Makoto Yoshikawa; Kent Yoshikawa; Shizuho Furuya; Kentaro Hatakeda; Tasuku Hayashi; Yuya Hitomi; Kazuya Kumagai; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Hiromichi Soejima; Ayako Iwamae; Daiki Yamamoto; Kasumi Yogata; Miwa Yoshitake; Ryota Fukai; Tomohiro Usui; Harold C. Connolly; Dante Lauretta; Sei-ichiro Watanabe; Yuichi Tsuda
    Science 379 6634 2022年10月 [査読有り]
     
    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 measure noble gas and nitrogen isotopes in Ryugu samples, finding they are dominated by pre-solar 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 heterogeneous abundances between the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating ~5 Myr exposure, and from implanted solar wind, record the recent irradiation history of Ryugu after it migrated to its current orbit.
  • T. Nakamura; M. Matsumoto; K. Amano; Y. Enokido; M. E. Zolensky; T. Mikouchi; H. Genda; S. Tanaka; M. Y. Zolotov; K. Kurosawa; S. Wakita; R. Hyodo; H. Nagano; D. Nakashima; Y. Takahashi; Y. Fujioka; M. Kikuiri; E. Kagawa; M. Matsuoka; A. J. Brearley; A. Tsuchiyama; M. Uesugi; J. Matsuno; Y. Kimura; M. Sato; R. E. Milliken; E. Tatsumi; S. Sugita; T. Hiroi; K. Kitazato; D. Brownlee; D. J. Joswiak; M. Takahashi; K. Ninomiya; T. Takahashi; T. Osawa; K. Terada; F. E. Brenker; B. J. Tkalcec; L. Vincze; R. Brunetto; A. Aléon-Toppani; Q. H. S. Chan; M. Roskosz; J.-C. Viennet; P. Beck; E. E. Alp; T. Michikami; Y. Nagaashi; T. Tsuji; Y. Ino; J. Martinez; J. Han; A. Dolocan; R. J. Bodnar; M. Tanaka; H. Yoshida; K. Sugiyama; A. J. King; K. Fukushi; H. Suga; S. Yamashita; T. Kawai; K. Inoue; A. Nakato; T. Noguchi; F. Vilas; A. R. Hendrix; C. Jaramillo-Correa; D. L. Domingue; G. Dominguez; Z. Gainsforth; C. Engrand; J. Duprat; S. S. Russell; E. Bonato; C. Ma; T. Kawamoto; T. Wada; S. Watanabe; R. Endo; S. Enju; L. Riu; S. Rubino; P. Tack; S. Takeshita; Y. Takeichi; A. Takeuchi; A. Takigawa; D. Takir; T. Tanigaki; A. Taniguchi; K. Tsukamoto; T. Yagi; S. Yamada; K. Yamamoto; Y. Yamashita; M. Yasutake; K. Uesugi; I. Umegaki; I. Chiu; T. Ishizaki; S. Okumura; E. Palomba; C. Pilorget; S. M. Potin; A. Alasli; S. Anada; Y. Araki; N. Sakatani; C. Schultz; O. Sekizawa; S. D. Sitzman; K. Sugiura; M. Sun; E. Dartois; E. De Pauw; Z. Dionnet; Z. Djouadi; G. Falkenberg; R. Fujita; T. Fukuma; I. R. Gearba; K. Hagiya; M. Y. Hu; T. Kato; T. Kawamura; M. Kimura; M. K. Kubo; F. Langenhorst; C. Lantz; B. Lavina; M. Lindner; J. Zhao; B. Vekemans; D. Baklouti; B. Bazi; F. Borondics; S. Nagasawa; G. Nishiyama; K. Nitta; J. Mathurin; T. Matsumoto; I. Mitsukawa; H. Miura; A. Miyake; Y. Miyake; H. Yurimoto; R. Okazaki; H. Yabuta; H. Naraoka; K. Sakamoto; S. Tachibana; H. C. Connolly; D. S. Lauretta; M. Yoshitake; M. Yoshikawa; K. Yoshikawa; K. Yoshihara; Y. Yokota; K. Yogata; H. Yano; Y. Yamamoto; D. Yamamoto; M. Yamada; T. Yamada; T. Yada; K. Wada; T. Usui; R. Tsukizaki; F. Terui; H. Takeuchi; Y. Takei; A. Iwamae; H. Soejima; K. Shirai; Y. Shimaki; H. Senshu; H. Sawada; T. Saiki; M. Ozaki; G. Ono; T. Okada; N. Ogawa; K. Ogawa; R. Noguchi; H. Noda; M. Nishimura; N. Namiki; S. Nakazawa; T. Morota; A. Miyazaki; A. Miura; Y. Mimasu; K. Matsumoto; K. Kumagai; T. Kouyama; S. Kikuchi; K. Kawahara; S. Kameda; T. Iwata; Y. Ishihara; M. Ishiguro; H. Ikeda; S. Hosoda; R. Honda; C. Honda; Y. Hitomi; N. Hirata; N. Hirata; T. Hayashi; M. Hayakawa; K. Hatakeda; S. Furuya; R. Fukai; A. Fujii; Y. Cho; M. Arakawa; M. Abe; S. Watanabe; Y. Tsuda
    Science 379 6634 2022年09月 [査読有り]
     
    Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed seventeen Ryugu samples measuring 1-8 mm. CO 2 -bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and Ca, Al-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed by aqueous alteration reactions at low temperature, high pH, and water/rock ratios < 1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate Ryugu’s parent body formed ~ 2 million years after the beginning of Solar System formation.
  • Motoo Ito; Naotaka Tomioka; Masayuki Uesugi; Akira Yamaguchi; Naoki Shirai; Takuji Ohigashi; Ming-Chang Liu; Richard C. Greenwood; Makoto Kimura; Naoya Imae; Kentaro Uesugi; Aiko Nakato; Kasumi Yogata; Hayato Yuzawa; Yu Kodama; Akira Tsuchiyama; Masahiro Yasutake; Ross Findlay; Ian A. Franchi; James A. Malley; Kaitlyn A. McCain; Nozomi Matsuda; Kevin D. McKeegan; Kaori Hirahara; Akihisa Takeuchi; Shun Sekimoto; Ikuya Sakurai; Ikuo Okada; Yuzuru Karouji; Masahiko Arakawa; Atsushi Fujii; Masaki Fujimoto; Masahiko Hayakawa; Naoyuki Hirata; Naru Hirata; Rie Honda; Chikatoshi Honda; Satoshi Hosoda; Yu-ichi Iijima; Hitoshi Ikeda; Masateru Ishiguro; Yoshiaki Ishihara; Takahiro Iwata; Kosuke Kawahara; Shota Kikuchi; Kohei Kitazato; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Yuya Mimasu; Akira Miura; Osamu Mori; Tomokatsu Morota; Satoru Nakazawa; Noriyuki Namiki; Hirotomo Noda; Rina Noguchi; Naoko Ogawa; Kazunori Ogawa; Tatsuaki Okada; Chisato Okamoto; Go Ono; Masanobu Ozaki; Takanao Saiki; Naoya Sakatani; Hirotaka Sawada; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Seiji Sugita; Yuto Takei; Hiroshi Takeuchi; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Ryudo Tsukizaki; Koji Wada; Manabu Yamada; Tetsuya Yamada; Yukio Yamamoto; Hajime Yano; Yasuhiro Yokota; Keisuke Yoshihara; Makoto Yoshikawa; Kent Yoshikawa; Ryota Fukai; Shizuho Furuya; Kentaro Hatakeda; Tasuku Hayashi; Yuya Hitomi; Kazuya Kumagai; Akiko Miyazaki; Masahiro Nishimura; Hiromichi Soejima; Ayako Iwamae; Daiki Yamamoto; Miwa Yoshitake; Toru Yada; Masanao Abe; Tomohiro Usui; Sei-ichiro Watanabe; Yuichi Tsuda
    Nature Astronomy 6 10 1163 - 1171 2022年08月 [査読有り]
     
    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.
  • Eizo NAKAMURA; Katsura KOBAYASHI; Ryoji TANAKA; Tak KUNIHIRO; Hiroshi KITAGAWA; Christian POTISZIL; Tsutomu OTA; Chie SAKAGUCHI; Masahiro YAMANAKA; Dilan M. RATNAYAKE; Havishk TRIPATHI; Rahul KUMAR; Maya-Liliana AVRAMESCU; Hidehisa TSUCHIDA; Yusuke YACHI; Hitoshi MIURA; Masanao ABE; Ryota FUKAI; Shizuho FURUYA; Kentaro HATAKEDA; Tasuku HAYASHI; Yuya HITOMI; Kazuya KUMAGAI; Akiko MIYAZAKI; Aiko NAKATO; Masahiro NISHIMURA; Tatsuaki OKADA; Hiromichi SOEJIMA; Seiji SUGITA; Ayako SUZUKI; Tomohiro USUI; Toru YADA; Daiki YAMAMOTO; Kasumi YOGATA; Miwa YOSHITAKE; Masahiko ARAKAWA; Atsushi FUJII; Masahiko HAYAKAWA; Naoyuki HIRATA; Naru HIRATA; Rie HONDA; Chikatoshi HONDA; Satoshi HOSODA; Yu-ichi IIJIMA; Hitoshi IKEDA; Masateru ISHIGURO; Yoshiaki ISHIHARA; Takahiro IWATA; Kosuke KAWAHARA; Shota KIKUCHI; Kohei KITAZATO; Koji MATSUMOTO; Moe MATSUOKA; Tatsuhiro MICHIKAMI; Yuya MIMASU; Akira MIURA; Tomokatsu MOROTA; Satoru NAKAZAWA; Noriyuki NAMIKI; Hirotomo NODA; Rina NOGUCHI; Naoko OGAWA; Kazunori OGAWA; Chisato OKAMOTO; Go ONO; Masanobu OZAKI; Takanao SAIKI; Naoya SAKATANI; Hirotaka SAWADA; Hiroki SENSHU; Yuri SHIMAKI; Kei SHIRAI; Yuto TAKEI; Hiroshi TAKEUCHI; Satoshi TANAKA; Eri TATSUMI; Fuyuto TERUI; Ryudo TSUKIZAKI; Koji WADA; Manabu YAMADA; Tetsuya YAMADA; Yukio YAMAMOTO; Hajime YANO; Yasuhiro YOKOTA; Keisuke YOSHIHARA; Makoto YOSHIKAWA; Kent YOSHIKAWA; Masaki FUJIMOTO; Sei-ichiro WATANABE; Yuichi TSUDA
    Proceedings of the Japan Academy, Series B 98 6 227 - 282 2022年06月 [査読有り]
  • Tetsuya Yokoyama; Kazuhide Nagashima; Izumi Nakai; Edward D. Young; Yoshinari Abe; Jérôme Aléon; Conel M. O’D. Alexander; Sachiko Amari; Yuri Amelin; Ken-ichi Bajo; Martin Bizzarro; Audrey Bouvier; Richard W. Carlson; Marc Chaussidon; Byeon-Gak Choi; Nicolas Dauphas; Andrew M. Davis; Tommaso Di Rocco; Wataru Fujiya; Ryota Fukai; Ikshu Gautam; Makiko K. Haba; Yuki Hibiya; Hiroshi Hidaka; Hisashi Homma; Peter Hoppe; Gary R. Huss; Kiyohiro Ichida; Tsuyoshi Iizuka; Trevor R. Ireland; Akira Ishikawa; Motoo Ito; Shoichi Itoh; Noriyuki Kawasaki; Noriko T. Kita; Kouki Kitajima; Thorsten Kleine; Shintaro Komatani; Alexander N. Krot; Ming-Chang Liu; Yuki Masuda; Kevin D. McKeegan; Mayu Morita; Kazuko Motomura; Frédéric Moynier; Ann Nguyen; Larry Nittler; Morihiko Onose; Andreas Pack; Changkun Park; Laurette Piani; Liping Qin; Sara S. Russell; Naoya Sakamoto; Maria Schönbächler; Lauren Tafla; Haolan Tang; Kentaro Terada; Yasuko Terada; Tomohiro Usui; Sohei Wada; Meenakshi Wadhwa; Richard J. Walker; Katsuyuki Yamashita; Qing-Zhu Yin; Shigekazu Yoneda; Hiroharu Yui; Ai-Cheng Zhang; Harold C. Connolly; Dante S. Lauretta; Tomoki Nakamura; Hiroshi Naraoka; Takaaki Noguchi; Ryuji Okazaki; Kanako Sakamoto; Hikaru Yabuta; Masanao Abe; Masahiko Arakawa; Atsushi Fujii; Masahiko Hayakawa; Naoyuki Hirata; Naru Hirata; Rie Honda; Chikatoshi Honda; Satoshi Hosoda; Yu-ichi Iijima; Hitoshi Ikeda; Masateru Ishiguro; Yoshiaki Ishihara; Takahiro Iwata; Kosuke Kawahara; Shota Kikuchi; Kohei Kitazato; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Yuya Mimasu; Akira Miura; Tomokatsu Morota; Satoru Nakazawa; Noriyuki Namiki; Hirotomo Noda; Rina Noguchi; Naoko Ogawa; Kazunori Ogawa; Tatsuaki Okada; Chisato Okamoto; Go Ono; Masanobu Ozaki; Takanao Saiki; Naoya Sakatani; Hirotaka Sawada; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Seiji Sugita; Yuto Takei; Hiroshi Takeuchi; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Yuichi Tsuda; Ryudo Tsukizaki; Koji Wada; Sei-ichiro Watanabe; Manabu Yamada; Tetsuya Yamada; Yukio Yamamoto; Hajime Yano; Yasuhiro Yokota; Keisuke Yoshihara; Makoto Yoshikawa; Kent Yoshikawa; Shizuho Furuya; Kentaro Hatakeda; Tasuku Hayashi; Yuya Hitomi; Kazuya Kumagai; Akiko Miyazaki; Aiko Nakato; Masahiro Nishimura; Hiromichi Soejima; Ayako Suzuki; Toru Yada; Daiki Yamamoto; Kasumi Yogata; Miwa Yoshitake; Shogo Tachibana; Hisayoshi Yurimoto
    Science 379 6634 2022年06月 [査読有り]
     
    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 measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to 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, (Stat.) (Syst.) million years after 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 the Sun’s photosphere than other natural samples do.
  • Shota Kikuchi; Sei-ichiro Watanabe; Koji Wada; Takanao Saiki; Hikaru Yabuta; Seiji Sugita; Masanao Abe; Masahiko Arakawa; Yuichiro Cho; Masahiko Hayakawa; Naoyuki Hirata; Naru Hirata; Chikatoshi Honda; Rie Honda; Ko Ishibashi; Yoshiaki Ishihara; Takahiro Iwata; Toshihiko Kadono; Shingo Kameda; Kohei Kitazato; Toru Kouyama; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Yuya Mimasu; Akira Miura; Tomokatsu Morota; Tomoki Nakamura; Satoru Nakazawa; Noriyuki Namiki; Rina Noguchi; Kazunori Ogawa; Naoko Ogawa; Tatsuaki Okada; Go Ono; Naoya Sakatani; Hirotaka Sawada; Hiroki Senshu; Yuri Shimaki; Kei Shirai; Shogo Tachibana; Yuto Takei; Satoshi Tanaka; Eri Tatsumi; Fuyuto Terui; Manabu Yamada; Yukio Yamamoto; Yasuhiro Yokota; Kent Yoshikawa; Makoto Yoshikawa; Yuichi Tsuda
    Planetary and Space Science 219 105519 - 105519 2022年06月 [査読有り]
  • S. Tachibana; H. Sawada; R. Okazaki; Y. Takano; K. Sakamoto; Y. N. Miura; C. Okamoto; H. Yano; S. Yamanouchi; P. Michel; Y. Zhang; S. Schwartz; F. Thuillet; H. Yurimoto; T. Nakamura; T. Noguchi; H. Yabuta; H. Naraoka; A. Tsuchiyama; N. Imae; K. Kurosawa; A. M. Nakamura; K. Ogawa; S. Sugita; T. Morota; R. Honda; S. Kameda; E. Tatsumi; Y. Cho; K. Yoshioka; Y. Yokota; M. Hayakawa; M. Matsuoka; N. Sakatani; M. Yamada; T. Kouyama; H. Suzuki; C. Honda; T. Yoshimitsu; T. Kubota; H. Demura; T. Yada; M. Nishimura; K. Yogata; A. Nakato; M. Yoshitake; A. I. Suzuki; S. Furuya; K. Hatakeda; A. Miyazaki; K. Kumagai; T. Okada; M. Abe; T. Usui; T. R. Ireland; M. Fujimoto; T. Yamada; M. Arakawa; H. C. Connolly; A. Fujii; S. Hasegawa; N. Hirata; N. Hirata; C. Hirose; S. Hosoda; Y. Iijima; H. Ikeda; M. Ishiguro; Y. Ishihara; T. Iwata; S. Kikuchi; K. Kitazato; D. S. Lauretta; G. Libourel; B. Marty; K. Matsumoto; T. Michikami; Y. Mimasu; A. Miura; O. Mori; K. Nakamura-Messenger; N. Namiki; A. N. Nguyen; L. R. Nittler; H. Noda; R. Noguchi; N. Ogawa; G. Ono; M. Ozaki; H. Senshu; T. Shimada; Y. Shimaki; K. Shirai; S. Soldini; T. Takahashi; Y. Takei; H. Takeuchi; R. Tsukizaki; K. Wada; Y. Yamamoto; K. Yoshikawa; K. Yumoto; M. E. Zolensky; S. Nakazawa; F. Terui; S. Tanaka; T. Saiki; M. Yoshikawa; S. Watanabe; Y. Tsuda
    Science 375 6584 1011 - 1016 2022年03月 [査読有り]
  • Tatsuhiro Michikami; Axel Hagermann; Tomokatsu Morota; Yasuhiro Yokota; Seitaro Urakawa; Hiroyuki Okamura; Naoya Tanabe; Koki Yumoto; Tatsuki Ebihara; Yuichiro Cho; Carolyn M. Ernst; Masahiko Hayakawa; Masatoshi Hirabayashi; Naru Hirata; Chikatoshi Honda; Rie Honda; Shingo Kameda; Masanori Kanamaru; Hiroshi Kikuchi; Shota Kikuchi; Toru Kouyama; Moe Matsuoka; Hideaki Miyamoto; Takaaki Noguchi; Rina Noguchi; Kazunori Ogawa; Tatsuaki Okada; Naoya Sakatani; Sho Sasaki; Hirotaka Sawada; Chiho Sugimoto; Hidehiko Suzuki; Satoshi Tanaka; Eri Tatsumi; Akira Tsuchiyama; Yuichi Tsuda; Sei-ichiro Watanabe; Manabu Yamada; Makoto Yoshikawa; Kazuo Yoshioka; Seiji Sugita
    Icarus 115007 - 115007 2022年03月 [査読有り]
  • Toru Yada; Masanao Abe; Tatsuaki Okada; Aiko Nakato; Kasumi Yogata; Akiko Miyazaki; Kentaro Hatakeda; Kazuya Kumagai; Masahiro Nishimura; Yuya Hitomi; Hiromichi Soejima; Miwa Yoshitake; Ayako Iwamae; Shizuho Furuya; Masayuki Uesugi; Yuzuru Karouji; Tomohiro Usui; Tasuku Hayashi; Daiki Yamamoto; Ryota Fukai; Seiji Sugita; Yuichiro Cho; Koki Yumoto; Yuna Yabe; Jean-Pierre Bibring; Cedric Pilorget; Vincent Hamm; Rosario Brunetto; Lucie Riu; Lionel Lourit; Damien Loizeau; Guillaume Lequertier; Aurelie Moussi-Soffys; Shogo Tachibana; Hirotaka Sawada; Ryuji Okazaki; Yoshinori Takano; Kanako Sakamoto; Yayoi N. Miura; Hajime Yano; Trevor R. Ireland; Tetsuya Yamada; Masaki Fujimoto; Kohei Kitazato; Noriyuki Namiki; Masahiko Arakawa; Naru Hirata; Hisayoshi Yurimoto; Tomoki Nakamura; Takaaki Noguchi; Hikaru Yabuta; Hiroshi Naraoka; Motoo Ito; Eizo Nakamura; Kentaro Uesugi; Katsura Kobayashi; Tatsuhiro Michikami; Hiroshi Kikuchi; Naoyuki Hirata; Yoshiaki Ishihara; Koji Matsumoto; Hirotomo Noda; Rina Noguchi; Yuri Shimaki; Kei Shirai; Kazunori Ogawa; Koji Wada; Hiroki Senshu; Yukio Yamamoto; Tomokatsu Morota; Rie Honda; Chikatoshi Honda; Yasuhiro Yokota; Moe Matsuoka; Naoya Sakatani; Eri Tatsumi; Akira Miura; Manabu Yamada; Atsushi Fujii; Chikako Hirose; Satoshi Hosoda; Hitoshi Ikeda; Takahiro Iwata; Shota Kikuchi; Yuya Mimasu; Osamu Mori; Naoko Ogawa; Go Ono; Takanobu Shimada; Stefania Soldini; Tadateru Takahashi; Yuto Takei; Hiroshi Takeuchi; Ryudo Tsukizaki; Kent Yoshikawa; Fuyuto Terui; Satoru Nakazawa; Satoshi Tanaka; Takanao Saiki; Makoto Yoshikawa; Sei-ichiro Watanabe; Yuichi Tsuda
    Nature Astronomy 6 2 214 - 220 2022年02月 [査読有り]
  • Yasuhiro Yokota; Rie Honda; Eri Tatsumi; Deborah Domingue; Stefan Schröder; Moe Matsuoka; Tomokatsu Morota; Naoya Sakatani; Shingo Kameda; Toru Kouyama; Manabu Yamada; Chikatoshi Honda; Masahiko Hayakawa; Yuichiro Cho; Tatsuhiro Michikami; Hidehiko Suzuki; Kazuo Yoshioka; Hirotaka Sawada; Kazunori Ogawa; Kouki Yumoto; Seiji Sugita
    Planetary Science Journal 2 5 2021年10月 [査読有り]
  • Naoya Tanabe; Yuichiro Cho; Eri Tatsumi; Tatsuki Ebihara; Koki Yumoto; Tatsuhiro Michikami; Hideaki Miyamoto; Tomokatsu Morota; Chikatoshi Honda; Patrick Michel; Katharina Otto; Olivier Barnouin; Kazuo Yoshioka; Hirotaka Sawada; Yasuhiro Yokota; Naoya Sakatani; Masahiro Hayakawa; Rie Honda; Shingo Kameda; Moe Matsuoka; Manabu Yamada; Toru Kouyama; Hidehiko Suzuki; Kazunori Ogawa; Seiji Sugita
    Planetary and Space Science 204 105249 - 105249 2021年09月 [査読有り]
  • Chiho Sugimoto; Eri Tatsumi; Yuichiro Cho; Tomokatsu Morota; Rie Honda; Shingo Kameda; Yosuhiro Yokota; Koki Yumoto; Minami Aoki; Daniella N. DellaGiustina; Tatsuhiro Michikami; Takahiro Hiroi; Deborah L. Domingue; Patrick Michel; Stefan E. Schröder; Tomoki Nakamura; Manabu Yamada; Naoya Sakatani; Toru Kouyama; Chikatoshi Honda; Masahiko Hayakawa; Moe Matsuoka; Hidehiko Suzuki; Kazuo Yoshioka; Kazunori Ogawa; Hirotaka Sawada; Masahiko Arakawa; Takanao Saiki; Hiroshi Imamura; Yasuhiko Takagi; Hajime Yano; Kei Shirai; Chisato Okamoto; Yuichi Tsuda; Satoru Nakazawa; Yuichi Iijima; Seiji Sugita
    Icarus 369 114591 - 114591 2021年06月 [査読有り]
  • Chiho Sugimoto; Eri Tatsumi; Yuichiro Cho; Tomokatsu Morota; Rie Honda; Shingo Kameda; Yosuhiro Yokota; Koki Yumoto; Minami Aoki; Daniella N. DellaGiustina; Tatsuhiro Michikami; Takahiro Hiroi; Deborah L. Domingue; Patrick Michel; Stefan E. Schröder; Tomoki Nakamura; Manabu Yamada; Naoya Sakatani; Toru Kouyama; Chikatoshi Honda; Masahiko Hayakawa; Moe Matsuoka; Hidehiko Suzuki; Kazuo Yoshioka; Kazunori Ogawa; Hirotaka Sawada; Masahiko Arakawa; Takanao Saiki; Hiroshi Imamura; Yasuhiko Takagi; Hajime Yano; Kei Shirai; Chisato Okamoto; Yuichi Tsuda; Satoru Nakazawa; Yuichi Iijima; Seiji Sugita
    Icarus 369 114529 - 114529 2021年05月 [査読有り]
  • Yuichiro Cho; Tomokatsu Morota; Masanori Kanamaru; Naofumi Takaki; Koki Yumoto; Carolyn M. Ernst; Masatoshi Hirabayashi; Olivier S. Barnouin; Eri Tatsumi; Katharina A. Otto; Nicole Schmitz; Roland J Wagner; Ralf Jaumann; Hideaki Miyamoto; Hiroshi Kikuchi; Ryodo Hemmi; Rie Honda; Shingo Kameda; Yasuhiro Yokota; Toru Kouyama; Hidehiko Suzuki; Manabu Yamada; Naoya Sakatani; Chikatoshi Honda; Masahiko Hayakawa; Kazuo Yoshioka; Moe Matsuoka; Tatsuhiro Michikami; Naru Hirata; Hirotaka Sawada; Kazunori Ogawa; Seiji Sugita
    2021年04月 [査読有り]
  • Tatsuhiro Michikami; Axel Hagermann
    Icarus 357 114282 - 114282 2021年03月 [査読有り]
  • Matthias Grott; Jens Biele; Patrick Michel; Seiji Sugita; Stefan Schröder; Naoya Sakatani; Wladimir Neumann; Shingo Kameda; Tatsuhiro Michikami; Chikatoshi Honda
    Journal of Geophysical Research: Planets 125 12 2020年12月 [査読有り]
  • Shota Kikuchi; Sei-ichiro Watanabe; Takanao Saiki; Hikaru Yabuta; Seiji Sugita; Tomokatsu Morota; Naru Hirata; Naoyuki Hirata; Tatsuhiro Michikami; Chikatoshi Honda; Yashuhiro Yokota; Rie Honda; Naoya Sakatani; Tatsuaki Okada; Yuri Shimaki; Koji Matsumoto; Rina Noguchi; Yuto Takei; Fuyuto Terui; Naoko Ogawa; Kent Yoshikawa; Go Ono; Yuya Mimasu; Hirotaka Sawada; Hitoshi Ikeda; Chikako Hirose; Tadateru Takahashi; Atsushi Fujii; Tomohiro Yamaguchi; Yoshiaki Ishihara; Tomoki Nakamura; Kohei Kitazato; Koji Wada; Shogo Tachibana; Eri Tatsumi; Moe Matsuoka; Hiroki Senshu; Shingo Kameda; Toru Kouyama; Manabu Yamada; Kei Shirai; Yuichiro Cho; Kazunori Ogawa; Yukio Yamamoto; Akira Miura; Takahiro Iwata; Noriyuki Namiki; Masahiko Hayakawa; Masanao Abe; Satoshi Tanaka; Makoto Yoshikawa; Satoru Nakazawa; Yuichi Tsuda
    Space Science Reviews 216 7 2020年10月 [査読有り]
  • E. Tatsumi; C. Sugimoto; L. Riu; S. Sugita; T. Nakamura; T. Hiroi; T. Morota; M. Popescu; T. Michikami; K. Kitazato; M. Matsuoka; S. Kameda; R. Honda; M. Yamada; N. Sakatani; T. Kouyama; Y. Yokota; C. Honda; H. Suzuki; Y. Cho; K. Ogawa; M. Hayakawa; H. Sawada; K. Yoshioka; C. Pilorget; M. Ishida; D. Domingue; N. Hirata; S. Sasaki; J. de León; M. A. Barucci; P. Michel; M. Suemitsu; T. Saiki; S. Tanaka; F. Terui; S. Nakazawa; S. Kikuchi; T. Yamaguchi; N. Ogawa; G. Ono; Y. Mimasu; K. Yoshikawa; T. Takahashi; Y. Takei; A. Fujii; Y. Yamamoto; T. Okada; C. Hirose; S. Hosoda; O. Mori; T. Shimada; S. Soldini; R. Tsukizaki; T. Mizuno; T. Iwata; H. Yano; M. Ozaki; M. Abe; M. Ohtake; N. Namiki; S. Tachibana; M. Arakawa; H. Ikeda; M. Ishiguro; K. Wada; H. Yabuta; H. Takeuchi; Y. Shimaki; K. Shirai; N. Hirata; Y. Iijima; Y. Tsuda; S. Watanabe; M. Yoshikawa
    Nature Astronomy 5 1 39 - 45 2020年09月 [査読有り]
  • T. Morota; S. Sugita; Y. Cho; M. Kanamaru; E. Tatsumi; N. Sakatani; R. Honda; N. Hirata; H. Kikuchi; M. Yamada; Y. Yokota; S. Kameda; M. Matsuoka; H. Sawada; C. Honda; T. Kouyama; K. Ogawa; H. Suzuki; K. Yoshioka; M. Hayakawa; N. Hirata; M. Hirabayashi; H. Miyamoto; T. Michikami; T. Hiroi; R. Hemmi; O. S. Barnouin; C. M. Ernst; K. Kitazato; T. Nakamura; L. Riu; H. Senshu; H. Kobayashi; S. Sasaki; G. Komatsu; N. Tanabe; Y. Fujii; T. Irie; M. Suemitsu; N. Takaki; C. Sugimoto; K. Yumoto; M. Ishida; H. Kato; K. Moroi; D. Domingue; P. Michel; C. Pilorget; T. Iwata; M. Abe; M. Ohtake; Y. Nakauchi; K. Tsumura; H. Yabuta; Y. Ishihara; R. Noguchi; K. Matsumoto; A. Miura; N. Namiki; S. Tachibana; M. Arakawa; H. Ikeda; K. Wada; T. Mizuno; C. Hirose; S. Hosoda; O. Mori; T. Shimada; S. Soldini; R. Tsukizaki; H. Yano; M. Ozaki; H. Takeuchi; Y. Yamamoto; T. Okada; Y. Shimaki; K. Shirai; Y. Iijima; H. Noda; S. Kikuchi; T. Yamaguchi; N. Ogawa; G. Ono; Y. Mimasu; K. Yoshikawa; T. Takahashi; Y. Takei; A. Fujii; S. Nakazawa; F. Terui; S. Tanaka; M. Yoshikawa; T. Saiki; S. Watanabe; Y. Tsuda
    Science 368 6491 654 - 659 2020年05月 [査読有り]
     
    The near-Earth asteroid (162173) Ryugu is thought to be a primitive carbonaceous object that contains hydrated minerals and organic molecules. We report sample collection from Ryugu’s surface by the Hayabusa2 spacecraft on 21 February 2019. Touchdown images and global observations of surface colors are used to investigate the stratigraphy of the surface around the sample location and across Ryugu. Latitudinal color variations suggest the reddening of exposed surface material by solar heating and/or space weathering. Immediately after touchdown, Hayabusa2’s thrusters disturbed dark, fine grains that originate from the redder materials. The stratigraphic relationship between identified craters and the redder material indicates that surface reddening occurred over a short period of time. We suggest that Ryugu previously experienced an orbital excursion near the Sun.
  • Tatsuaki Okada; Tetsuya Fukuhara; Satoshi Tanaka; Makoto Taguchi; Takehiko Arai; Hiroki Senshu; Naoya Sakatani; Yuri Shimaki; Hirohide Demura; Yoshiko Ogawa; Kentaro Suko; Tomohiko Sekiguchi; Toru Kouyama; Jun Takita; Tsuneo Matsunaga; Takeshi Imamura; Takehiko Wada; Sunao Hasegawa; Jörn Helbert; Thomas G. Müller; Axel Hagermann; Jens Biele; Matthias Grott; Maximilian Hamm; Marco Delbo; Naru Hirata; Naoyuki Hirata; Yukio Yamamoto; Seiji Sugita; Noriyuki Namiki; Kohei Kitazato; Masahiko Arakawa; Shogo Tachibana; Hitoshi Ikeda; Masateru Ishiguro; Koji Wada; Chikatoshi Honda; Rie Honda; Yoshiaki Ishihara; Koji Matsumoto; Moe Matsuoka; Tatsuhiro Michikami; Akira Miura; Tomokatsu Morota; Hirotomo Noda; Rina Noguchi; Kazunori Ogawa; Kei Shirai; Eri Tatsumi; Hikaru Yabuta; Yasuhiro Yokota; Manabu Yamada; Masanao Abe; Masahiko Hayakawa; Takahiro Iwata; Masanobu Ozaki; Hajime Yano; Satoshi Hosoda; Osamu Mori; Hirotaka Sawada; Takanobu Shimada; Hiroshi Takeuchi; Ryudo Tsukizaki; Atsushi Fujii; Chikako Hirose; Shota Kikuchi; Yuya Mimasu; Naoko Ogawa; Go Ono; Tadateru Takahashi; Yuto Takei; Tomohiro Yamaguchi; Kent Yoshikawa; Fuyuto Terui; Takanao Saiki; Satoru Nakazawa; Makoto Yoshikawa; Seiichiro Watanabe; Yuichi Tsuda
    Nature 579 7800 518 - 522 2020年03月 [査読有り]
     
    Carbonaceous (C-type) asteroids1 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 chondrites2,3 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 Hayabusa25, 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 chondrites6 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 effect7,8. 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 chondrites6. These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity9 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 bodies10.
  • Tatsuhiro Michikami; Axel Hagermann; Akira Tsuchiyama; Hirotaka Yamaguchi; Terunori Irie; Keita Nomura; Osamu Sasaki; Michihiko Nakamura; Satoshi Okumura; Sunao Hasegawa
    Planetary and Space Science 177 104690 (14pp.) 104690 - 104690 2019年11月 [査読有り]
  • Tatsuhiro Michikami; Chikatoshi Honda; Hideaki Miyamoto; Masatoshi Hirabayashi; Axel Hagermann; Terunori Irie; Keita Nomura; Carolyn M. Ernst; Masaki Kawamura; Kiichi Sugimoto; Eri Tatsumi; Tomokatsu Morota; Naru Hirata; Takaaki Noguchi; Yuichiro Cho; Shingo Kameda; Toru Kouyama; Yasuhiro Yokota; Rina Noguchi; Masahiko Hayakawa; Naoyuki Hirata; Rie Honda; Moe Matsuoka; Naoya Sakatani; Hidehiko Suzuki; Manabu Yamada; Kazuo Yoshioka; Hirotaka Sawada; Ryodo Hemmi; Hiroshi Kikuchi; Kazunori Ogawa; Sei ichiro Watanabe; Satoshi Tanaka; Makoto Yoshikawa; Yuichi Tsuda; Seiji Sugita
    Icarus 331 179 - 191 2019年10月 [査読有り]
  • S. Watanabe; M. Hirabayashi; N. Hirata; Na. Hirata; R. Noguchi; Y. Shimaki; H. Ikeda; E. Tatsumi; M. Yoshikawa; S. Kikuchi; H. Yabuta; T. Nakamura; S. Tachibana; Y. Ishihara; T. Morota; K. Kitazato; N. Sakatani; K. Matsumoto; K. Wada; H. Senshu; C. Honda; T. Michikami; H. Takeuchi; T. Kouyama; R. Honda; S. Kameda; T. Fuse; H. Miyamoto; G. Komatsu; S. Sugita; T. Okada; N. Namiki; M. Arakawa; M. Ishiguro; M. Abe; R. Gaskell; E. Palmer; O. S. Barnouin; P. Michel; A. S. French; J. W. McMahon; D. J. Scheeres; P. A. Abell; Y. Yamamoto; S. Tanaka; K. Shirai; M. Matsuoka; M. Yamada; Y. Yokota; H. Suzuki; K. Yoshioka; Y. Cho; S. Tanaka; N. Nishikawa; T. Sugiyama; H. Kikuchi; R. Hemmi; T. Yamaguchi; N. Ogawa; G. Ono; Y. Mimasu; K. Yoshikawa; T. Takahashi; Y. Takei; A. Fujii; C. Hirose; T. Iwata; M. Hayakawa; S. Hosoda; O. Mori; H. Sawada; T. Shimada; S. Soldini; H. Yano; R. Tsukizaki; M. Ozaki; Y. Iijima; K. Ogawa; M. Fujimoto; T.-M. Ho; A. Moussi; R. Jaumann; J.-P. Bibring; C. Krause; F. Terui; T. Saiki; S. Nakazawa; Y. Tsuda
    Science 364 6437 268 - 272 2019年04月 [査読有り]
     
    The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.
  • Seitaro Urakawa; Ryou Ohsawa; Shigeyuki Sako; Shin-ichiro Okumura; Yuri Sakurai; Jun Takahashi; Kazuyoshi Imamura; Hiroyuki Naito; Fumitake Watanabe; Ryoma Nagayoshi; Yasuhiko Murakami; Ryo Okazaki; Tomohiko Sekiguchi; Masateru Ishiguro; Tatsuhiro Michikami; Makoto Yoshikawa
    The Astronomical Journal 157 155 2019年04月 [査読有り]
  • Masatoshi Hirabayashi; Eri Tatsumi; Hideaki Miyamoto; Goro Komatsu; Seiji Sugita; Sei Ichiro Watanabe; Daniel J. Scheeres; Olivier S. Barnouin; Patrick Michel; Chikatoshi Honda; Tatsuhiro Michikami; Yuichiro Cho; Tomokatsu Morota; Naru Hirata; Naoyuki Hirata; Naoya Sakatani; Stephen R. Schwartz; Rie Honda; Yasuhiro Yokota; Shingo Kameda; Hidehiko Suzuki; Toru Kouyama; Masahiko Hayakawa; Moe Matsuoka; Kazuo Yoshioka; Kazunori Ogawa; Hirotaka Sawada; Makoto Yoshikawa; Yuichi Tsuda
    Astrophysical Journal Letters 874 1 2019年03月 [査読有り]
  • Sugita, S.; Honda, R.; Morota, T.; Kameda, S.; Sawada, H.; Tatsumi, E.; Yamada, M.; Honda, C.; Yokota, Y.; Kouyama, T.; Sakatani, N.; Ogawa, K.; Suzuki, H.; Okada, T.; Namiki, N.; Tanaka, S.; Iijima, Y.; Yoshioka, K.; Hayakawa, M.; Cho, Y.; Matsuoka, M.; Hirata, N.; Hirata, N.; Miyamoto, H.; Domingue, D.; Hirabayashi, M.; Nakamura, T.; Hiroi, T.; Michikami, T.; Michel, P.; Ballouz, R.-L.; Barnouin, O. S.; Ernst, C. M.; Schr{\"o}der, S. E.; Kikuchi, H.; Hemmi, R.; Komatsu, G.; Fukuhara, T.; Taguchi, M.; Arai, T.; Senshu, H.; Demura, H.; Ogawa, Y.; Shimaki, Y.; Sekiguchi, T.; M{\"u}ller, T. G.; Hagermann, A.; Mizuno, T.; Noda, H.; Matsumoto, K.; Yamada, R.; Ishihara, Y.; Ikeda, H.; Araki, H.; Yamamoto, K.; Abe, S.; Yoshida, F.; Higuchi, A.; Sasaki, S.; Oshigami, S.; Tsuruta, S.; Asari, K.; Tazawa, S.; Shizugami, M.; Kimura, J.; Otsubo, T.; Yabuta, H.; Hasegawa, S.; Ishiguro, M.; Tachibana, S.; Palmer, E.; Gaskell, R.; Le Corre, L.; Jaumann, R.; Otto, K.; Schmitz, N.; Abell, P. A.; Barucci, M. A.; Zolensky, M. E.; Vilas, F.; Thuillet, F.; Sugimoto, C.; Takaki, N.; Suzuki, Y.; Kamiyoshihara, H.; Okada, M.; Nagata, K.; Fujimoto, M.; Yoshikawa, M.; Yamamoto, Y.; Shirai, K.; Noguchi, R.; Ogawa, N.; Terui, F.; Kikuchi, S.; Yamaguchi, T.; Oki, Y.; Takao, Y.; Takeuchi, H.; Ono, G.; Mimasu, Y.; Yoshikawa, K.; Takahashi, T.; Takei, Y.; Fujii, A.; Hirose, C.; Nakazawa, S.; Hosoda, S.; Mori, O.; Shimada, T.; Soldini, S.; Iwata, T.; Abe, M.; Yano, H.; Tsukizaki, R.; Ozaki, M.; Nishiyama, K.; Saiki, T.; Watanabe, S.; Tsuda, Y.
    Science 364 6437 2019年 [査読有り]
  • Wada, K.; Grott, M.; Michel, P.; Walsh, K.J.; Barucci, A.M.; Biele, J.; Blum, J.; Ernst, C.M.; Grundmann, J.T.; Gundlach, B.; Hagermann, A.; Hamm, M.; Jutzi, M.; Kim, M.-J.; K{\"u}hrt, E.; Le Corre, L.; Libourel, G.; Lichtenheldt, R.; Maturilli, A.; Messenger, S.R.; Michikami, T.; Miyamoto, H.; Mottola, S.; M{\"u}ller, T.; Nakamura, A.M.; Nittler, L.R.; Ogawa, K.; Okada, T.; Palomba, E.; Sakatani, N.; Schr{\"o}der, S.E.; Senshu, H.; Takir, D.; Zolensky, M.E.
    Progress in Earth and Planetary Science 5 1 2018年11月 [査読有り]
  • Tatsuhiro Michikami; Tokiyuki Kadokawa; Akira Tsuchiyama; Axel Hagermann; Tsukasa Nakano; Kentaro Uesugi; Sunao Hasegawa
    Icarus 302 109 - 125 2018年03月 [査読有り]
  • Michael E. Zolensky; Neyda M. Abreu; Michael A. Velbel; Alan Rubin; Noel Chaumard; Takaaki Noguchi; Tatsuhiro Michikami
    Primitive Meteorites and Asteroids: Physical, Chemical, and Spectroscopic Observations Paving the Way to Exploration 59 - 204 2018年01月
  • T. Kaku; J. Haruyama; W. Miyake; A. Kumamoto; K. Ishiyama; T. Nishibori; K. Yamamoto; Sarah T. Crites; T. Michikami; Y. Yokota; R. Sood; H. J. Melosh; L. Chappaz; K. C. Howell
    GEOPHYSICAL RESEARCH LETTERS 44 20 10155 - 10161 2017年10月 [査読有り]
  • Kim, Y.; Ishiguro, M.; Michikami, T.; Nakamura, A.M.
    Astronomical Journal 153 5 228 - 238 2017年04月 [査読有り]
  • Tatsuhiro Michikami; Axel Hagermann; Tomokatsu Morota; Junichi Haruyama; Sunao Hasegawa
    PLANETARY AND SPACE SCIENCE 135 27 - 36 2017年01月 [査読有り]
  • HARUYAMA Junichi; NAGAMATSU Aiko; SHIMADA Kazuhito; HASENAKA Toshiaki; MOROTA Tomokatsu; NISHINO Masaki N; HASHIZUME Ko; SAIKI Kazuto; SHIRA Motomaro; KOMATSU Goro; HASEBE Nobuyuki; KAWANO Isao; SHIMIZU Hisayoshi; MIYAMOTO Hideaki; KOBAYASHI Kensei; YOKOBORI Shinichi; MICHIKAMI Tatsuhiro; YAMAMOTO Satoru; YOKOTA Yasuhiro; ARISUMI Hitoshi; ISHIGAMI Genya; FURUTANI Katsushi; KUBOTA Takashi; MICHIKAWA Yuichi; OTSUKI Masatsugu; KATO Hiroki; NISHIBORI Toshihiko; IWATA Takahiro; YAMAMOTO Yukio; ISHIHARA Yoshiaki
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 14 30 Pk_147 - Pk_150 一般社団法人 日本航空宇宙学会 2016年 
    <p>We are planning to explore the caverns through the skylight holes on the Moon and Mars. The holes and their associated subsurface caverns are among the most important future exploration targets. The importance of the lunar and Martian holes and their associated caverns is categorized from two aspects: (1) fresh materials are easily observed and sampled there, and (2) the subsurface caverns provide a safe, quiet environment. The expectation of lunar and Martian hole and cavern exploration is increasing in Japan. We name the project as UZUME (Unprecedented Zipangu (Japan) Underworld of the Moon Exploration) whose name is after a Japanese mythology. The ultimate purpose of the UZUME project is to investigate how to expand human activity and survival in space and on extraterrestrial bodies.<i><b> </b></i></p>
  • Tatsuhiro Michikami; Axel Hagermann; Tokiyuki Kadokawa; Akifumi Yoshida; Akira Shimada; Sunao Hasegawa; Akira Tsuchiyama
    ICARUS 264 316 - 330 2016年01月 [査読有り]
  • 道上 達広; 長谷川直; 春山純一
    日本惑星科学会誌 遊星人 24 3 225 - 232 日本惑星科学会 2015年09月 [査読有り]
     
    月や火星には深さ・直径共に数10mから100mにおよぶ縦孔が近年,探査機によって多数観測されるようになった.また縦孔の中には,地下空洞に開いた「天窓」であることが確実なものもある.こうした縦孔は,科学的に多くの興味があるとともに将来的に人類が月や火星に進出したとき,長期滞在に適する基地として有望な場所でもある.月の大きな縦孔については,地下空洞の天井に隕石衝突が引き金となって形成された可能性が示唆されている.本研究では,月に見られる楕円形の大きな縦孔が,隕石の斜め衝突によって形成された可能性を,実験的研究によって明らかにした.
  • T. Michikami; A. Hagermann; H. Miyamoto; S. Miura; J. Haruyama; P. S. Lykawka
    PLANETARY AND SPACE SCIENCE 96 71 - 80 2014年06月 [査読有り]
  • Akira Tsuchiyama; Masayuki Uesugi; Takashi Matsushima; Tatsuhiro Michikami; Toshihiko Kadono; Tomoki Nakamura; Kentaro Uesugi; Tsukasa Nakano; Scott A Sandford; Ryo Noguchi; Toru Matsumoto; Junya Matsuno; Takashi Nagano; Yuta Imai; Akihisa Takeuchi; Yoshio Suzuki; Toshihiro Ogami; Jun Katagiri; Mitsuru Ebihara; Trevor R Ireland; Fumio Kitajima; Keisuke Nagao; Hiroshi Naraoka; Takaaki Noguchi; Ryuji Okazaki; Hisayoshi Yurimoto; Michael E Zolensky; Toshifumi Mukai; Masanao Abe; Toru Yada; Akio Fujimura; Makoto Yoshikawa; Junichiro Kawaguchi
    Science (New York, N.Y.) 333 6046 1125 - 8 2011年08月 [査読有り]
     
    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.
  • Tatsuhiro Michikami; Akiko M. Nakamura; Naru Hirata
    ICARUS 207 1 277 - 284 2010年05月 [査読有り]
  • Naru Hirata; Olivier S. Barnouin-Jha; Chikatoshi Honda; Ryosuke Nakamura; Hideaki Miyamoto; Sho Sasaki; Hirohide Demura; Akiko M. Nakamura; Tatsuhiro Michikami; Robert W. Gaskell; Jun Saito
    ICARUS 200 2 486 - 502 2009年04月 [査読有り]
  • Hirata, N; Honda, C; Nakamura, R; Miyamoto, H; Sasaki, S; Demura, H; Nakamura, A. M; Michikami, T; Barnouin-Jha, O.S; Gaskell, R.W; Saito, J
    Icarus 200, 486-502 2009年04月 [査読有り]
  • Tatsuhiro Michikami; Akiko M. Nakamura; Naru Hirata; Robert W. Gaskell; Ryosuke Nakamura; Takayuki Honda; Chikatoshi Honda; Kensuke Hiraoka; Jun Saito; Hirohide Demura; Masateru Ishiguro; Hideaki Miyamoto
    EARTH PLANETS AND SPACE 60 1 13 - 20 2008年 [査読有り]
  • A. M. Nakamura; T. Michikami; N. Hirata; A. Fujiwara; R. Nakamura; M. Ishiguro; H. Miyamoto; H. Demura; K. Hiraoka; T. Honda; C. Honda; J. Saito; T. Hashimoto; T. Kubota
    EARTH PLANETS AND SPACE 60 1 7 - 12 2008年 [査読有り]
  • Hideaki Miyamoto; Hajime Yano; Daniel J. Scheeres; Shinsuke Abe; Olivier Barnouin-Jha; Andrew F. Cheng; Hirohide Demura; Robert W. Gaskell; Naru Hirata; Masateru Ishiguro; Tatsuhiro Michikami; Akiko M. Nakamura; Ryosuke Nakamura; Jun Saito; Sho Sasaki
    SCIENCE 316 5827 1011 - 1014 2007年05月 [査読有り]
  • Tatsuhiro Michikami; Kouichi Moriguchi; Sunao Hasegawa; Akira Fujiwara
    PLANETARY AND SPACE SCIENCE 55 1-2 70 - 88 2007年01月 [査読有り]
  • J Saito; H Miyamoto; R Nakamura; M Ishiguro; T Michikami; AM Nakamura; H Demura; S Sasaki; N Hirata; C Honda; A Yamamoto; Y Yokota; T Fuse; F Yoshida; DJ Tholen; RW Gaskell; T Hashimoto; T Kubota; Y Higuchi; T Nakamura; P Smith; K Hiraoka; T Honda; S Kobayashi; M Furuya; N Matsumoto; E Nemoto; A Yukishita; K Kitazato; B Dermawan; A Sogame; J Terazono; C Shinohara; H Akiyama
    SCIENCE 312 5778 1341 - 1344 2006年06月 [査読有り]
  • 福島高専物理教育におけるビデオオンデマンドを利用したeランニング教材の開発
    布施雅彦; 鈴木三男; 根本信行; 道上達広; 小澤哲
    高専教育 29 439 - 444 2006年03月 [査読有り]
  • Y Hirase; AM Nakamura; T Michikami
    PLANETARY AND SPACE SCIENCE 52 12 1103 - 1108 2004年10月 [査読有り]
  • 小惑星25143イトカワのレゴリス厚さと岩塊（ブロック）の数密度の推定
    道上達広
    日本惑星科学会誌 遊星人 13 2 71 - 79 2004年 [査読有り]
  • T. Takano; M. Yoshikawa; Y. Ishibashi; T. Michikami; J. Watanabe; T. Nakamura; T. Tajima; M. Toda; B. Suzuki
    Science and Technology Series 100 75 - 84 2001年
  • 小惑星レゴリス衝突進化
    道上達広; 山本聡; 長沢真樹子; 中澤暁
    日本惑星科学会誌 遊星人 9 4 186 - 196 2000年 [査読有り]

MISC

  • Kikuchi Shota; Watanabe Sei-ichiro; Watanabe Sei-ichiro; Saiki Takanao; Yabuta Hikaru; Sugita Seiji; Sugita Seiji; Sugita Seiji; Morota Tomokatsu; Morota Tomokatsu; Hirata Naru; Hirata Naoyuki; Michikami Tatsuhiro; Honda Chikatoshi; Yokota Yashuhiro; Honda Rie; Sakatani Naoya; Sakatani Naoya; Okada Tatsuaki; Shimaki Yuri; Matsumoto Koji; Noguchi Rina; Takei Yuto; Terui Fuyuto; Ogawa Naoko; Yoshikawa Kent; Ono Go; Mimasu Yuya; Sawada Hirotaka; Ikeda Hitoshi; Hirose Chikako; Takahashi Tadateru; Takahashi Tadateru; Fujii Atsushi; Yamaguchi Tomohiro; Yamaguchi Tomohiro; Ishihara Yoshiaki; Ishihara Yoshiaki; Nakamura Tomoki; Kitazato Kohei; Wada Koji; Tachibana Shogo; Tachibana Shogo; Tatsumi Eri; Tatsumi Eri; Matsuoka Moe; Senshu Hiroki; Kameda Shingo; Kouyama Toru; Yamada Manabu; Shirai Kei; Shirai Kei; Cho Yuichiro; Ogawa Kazunori; Ogawa Kazunori; Yamamoto Yukio; Miura Akira; Iwata Takahiro; Namiki Noriyuki; Hayakawa Masahiko; Abe Masanao; Tanaka Satoshi; Yoshikawa Makoto; Nakazawa Satoru; Tsuda Yuichi Space Science Reviews 216 (7) 2020年
  • 土山 明; 松島 亘志; 中野 司; 道上 達広; 上杉 健太朗; 竹内 晃久; 鈴木 芳生; 松本 徹; 島田 玲; 松野 淳也; 門野 敏彦; 大竹 真紀子 日本鉱物科学会年会講演要旨集 2013 156 -156 2013年09月
  • 土`山 明; 野口 遼; 松本 徹; 松野 淳也; 永野 崇; 今井 悠太; 竹内 晃久; 鈴木 芳生; 大神 稔皓; 片桐 淳; 海老原 充; 上椙 真之; アイルランド トレバー; 北島 富美雄; 長尾 敬介; 奈良岡 浩; 野口 高明; 岡崎 隆司; 圦本 尚義; ゾレンスキー マイク; 向井 利典; 安部 正真; 松島 亘志; 矢田 達; 藤村 彰夫; 吉川 真; 川口 淳一郎; 道上 達広; 門野 敏彦; 中村 智樹; 上杉 健太朗; 中野 司; サンドフォード スコット 日本地質学会学術大会講演要旨 2011 (0) 1 -1 2011年
  • 土山 明; 野口 遼; 松本 徹; 松野 淳也; 永野 崇; 今井 悠太; 竹内 晃久; 鈴木 芳生; 大神 稔皓; 片桐 淳; 海老原 充; 上椙 真之; アイルランド トレバー; 北島 富美雄; 長尾 敬介; 奈良岡 浩; 野口 高明; 岡崎 隆司; 圦本 尚義; ゾレンスキー マイケル; はやぶさ キュレーションチーム; 松島 亘志; 道上 達広; 門野 敏彦; 中村 智樹; 上杉 健太朗; 中野 司; スコット サンドフォード 日本地球化学会年会要旨集 58 (0) 169 -169 2011年
  • 道上 達広; 中村 昭子; 平田 成 日本惑星科学会秋季講演会予稿集 2007 (0) 79 -79 2007年
  • 平田 成; 出村 裕英; 中村 良介; 阿部 新助; 中村 昭子; 道上 達広; 野口 高明; 佐々木 晶 日本惑星科学会秋季講演会予稿集 2007 (0) 78 -78 2007年
  • 平田 成; 中村 良介; 本田 親寿; 中村 昭子; 出村 裕英; 道上 達広; 宮本 英昭; 齋藤 潤 日本惑星科学会秋季講演会予稿集 2006 (0) 73 -73 2006年

書籍等出版物

所属学協会

  • 日本惑星科学会   The Japanese Society for Planetary Science   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 道上 達広
     
    最近の研究で、小惑星リュウグウに含水鉱物の形で水が存在することが発見された。近年、地球の水は小惑星リュウグウのような炭素質小惑星から供給された可能性が大きいと考えられている。その供給形態の１つとして、小惑星表層のレゴリス層と呼ばれる細粒の粒子が、宇宙空間に放出され、惑星間塵として地球にもたらされることが挙げられる。しかしながら、小惑星リュウグウのような微小重力下で、どのようにレゴリス層が形成されたかよく分かっていない。 レゴリス層の主要な形成要因として、小惑星の昼夜の温度差がもたらす熱疲労による表面物質の細粒化、隕石衝突による破片の再集積の２つが考えられる。表面物質が細粒化された場合、太陽風や微小隕石による宇宙風化作用で、小惑星表面のスペクトルが変化する。また、隕石衝突によるクレーター形成やそれに伴う表層のガーデニングなど、小惑星表面は当初あった状態から変化する。 本研究では、レゴリス層は隕石衝突によって形成されたとの立場で、炭素質小惑星と同じ炭素質隕石に対して衝突実験を行い、衝突破片を調べることにした。具体的には、衝突前後の炭素質隕石の内部構造をX線CT撮像することで、クラックの空間分布、特にコンドリュール中のクラックの進展を調べた。学術的な問いは、「炭素質小惑星のレゴリス層形成は、衝突破片の再集積か？」である。 2020年度は、CV隕石であるアエンデ隕石に対して、2021年度は、CM隕石であるマーチソン隕石、アグアス・ザルカス隕石に対して実験を行った。その結果、コンドリュール中のクラック進展はCV隕石とCM隕石で異なることが分かった。これはCM隕石が水質変成作用を受けていることが原因であることが本研究によって初めて分かった。2023年度に小惑星ベンヌ（CM隕石と同じ物質）からサンプル粒子が地球に持ち帰られることから、比較研究で地球の水の起源に迫ることが期待される。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2010年 -2011年 
    代表者 : 道上 達広
     
    小惑星探査機はやぶさの観測データから、小惑星イトカワのような500mサイズの小さな天体表面にも多くの衝突破片(岩塊)によって覆われていることが明らかになった。しかしながら、低重力の小惑星が、なぜ多くの破片を捕獲、保持できたのか分かっていない。そこで本研究では、観測された小惑星の空隙率が高いことに注目し、小惑星を模擬した多孔質物質に対して高速度衝突破壊実験を行い、飛び出した破片速度が、空隙率などの衝突条件によってどのように変わるかを詳細に調べた。その結果、破片速度を代表する衝突反対点の破片速度は標的の空隙率よりも衝撃波の減衰率に強く影響を受けることが分かった。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2006年 -2008年 
    代表者 : 三浦 靖一郎; 渡辺 博; 春日 健; 井川 治; 道上 達広; 布施 雅彦
     
    青少年の科学技術への興味関心を高めるために,ものづくりの要素を取り入れた初心者向け工学教育教材の開発を行った.教材は,科学技術の各分野を横断的に取り扱えるモデルロケットを通して組み立て,学習教材付きモデルロケット設計支援ソフト,論理回路の基礎を含んだ発射台・発射装置の作り方,積載用電気電子装置の作り方などを作成した.公開講座の実習状況や調査結果等より,初心者用教材としての一定の効果を確認した.
  • Formation and Evolution of Asteroid
    The Other Research Programs
    研究期間 : 1998年 -2008年
  • 小惑星（惑星）の起源、進化に関する研究
    共同研究

その他のリンク

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