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Author

Hikaru Yabuta

Bio: Hikaru Yabuta is an academic researcher from Hiroshima University. The author has contributed to research in topics: Asteroid & Chondrite. The author has an hindex of 22, co-authored 91 publications receiving 3645 citations. Previous affiliations of Hikaru Yabuta include Osaka University & Carnegie Institution for Science.
Topics: Asteroid, Chondrite, Astrobiology, Meteorite, Medicine


Papers
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Journal ArticleDOI
15 Dec 2006-Science
TL;DR: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study, and preliminary examination shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin.
Abstract: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

886 citations

Journal ArticleDOI
15 Dec 2006-Science
TL;DR: The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage and a diverse suite of organic compounds is present and identifiable within the returned samples.
Abstract: Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.

547 citations

Journal ArticleDOI
TL;DR: In a survey of the elemental and isotopic compositions of insoluble organic matter (IOM) from 75 carbonaceous, ordinary and enstatite chondrites, this article found dramatic variations within and between chondrite classes.

496 citations

Journal ArticleDOI
Sei-ichiro Watanabe1, Sei-ichiro Watanabe2, Masatoshi Hirabayashi3, Naru Hirata4, Na. Hirata5, Rina Noguchi1, Yuri Shimaki1, H. Ikeda, Eri Tatsumi6, Makoto Yoshikawa7, Makoto Yoshikawa1, Shota Kikuchi1, Hikaru Yabuta8, Tomoki Nakamura9, Shogo Tachibana1, Shogo Tachibana6, Yoshiaki Ishihara1, Tomokatsu Morota2, Kohei Kitazato4, Naoya Sakatani1, Koji Matsumoto7, Koji Wada10, Hiroki Senshu10, C. Honda4, Tatsuhiro Michikami11, Hiroshi Takeuchi7, Hiroshi Takeuchi1, Toru Kouyama12, R. Honda13, Shingo Kameda14, Tetsuharu Fuse15, Hideaki Miyamoto6, Goro Komatsu10, S. Sugita6, Tatsuaki Okada1, Tatsuaki Okada6, Noriyuki Namiki7, Masahiko Arakawa5, Masateru Ishiguro16, Masanao Abe1, Masanao Abe7, Robert Gaskell17, Eric Palmer17, Olivier S. Barnouin18, Patrick Michel19, A. S. French20, Jay W. McMahon20, Daniel J. Scheeres20, Paul A. Abell, Yukio Yamamoto7, Yukio Yamamoto1, Satoshi Tanaka7, Satoshi Tanaka1, Kei Shirai1, Moe Matsuoka1, Manabu Yamada10, Y. Yokota13, Y. Yokota1, H. Suzuki21, Kosuke Yoshioka6, Yuichiro Cho6, Naoki Nishikawa5, T. Sugiyama4, Hideaki Kikuchi6, Ryodo Hemmi6, Tomohiro Yamaguchi1, Naoko Ogawa1, Go Ono, Yuya Mimasu1, Kent Yoshikawa, T. Takahashi1, Yuto Takei1, Atsushi Fujii1, Chikako Hirose, Takahiro Iwata7, Takahiro Iwata1, Masahiro Hayakawa1, Satoshi Hosoda1, Osamu Mori1, Hirotaka Sawada1, Takanobu Shimada1, Stefania Soldini1, Hajime Yano1, Hajime Yano7, Ryudo Tsukizaki1, M. Ozaki1, M. Ozaki7, Yuichi Iijima1, K. Ogawa5, Masaki Fujimoto1, T. M. Ho22, Aurelie Moussi23, Ralf Jaumann, J. P. Bibring, Christian Krause, Fuyuto Terui1, Takanao Saiki1, Satoru Nakazawa1, Yoshiyuki Tsuda7, Yoshiyuki Tsuda1 
19 Mar 2019-Science
TL;DR: The Hayabusa2 spacecraft measured the mass, size, shape, density, and spin rate of asteroid Ryugu, showing that it is a porous rubble pile, and observations of Ryugu's shape, mass, and geomorphology suggest that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation.
Abstract: 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.

402 citations

Journal ArticleDOI
Seiji Sugita1, Seiji Sugita2, Rie Honda3, Tomokatsu Morota4, Shingo Kameda5, Hirotaka Sawada6, Eri Tatsumi2, Manabu Yamada1, C. Honda7, Yasuhiro Yokota6, Yasuhiro Yokota3, Toru Kouyama8, Naoya Sakatani6, K. Ogawa9, H. Suzuki10, Tatsuaki Okada2, Tatsuaki Okada6, Noriyuki Namiki11, Satoshi Tanaka6, Satoshi Tanaka11, Yuichi Iijima6, Kosuke Yoshioka2, Masahiro Hayakawa6, Yuichiro Cho2, Moe Matsuoka6, Naru Hirata7, Hideaki Miyamoto2, Deborah L. Domingue12, Masatoshi Hirabayashi13, Tomoki Nakamura14, Takahiro Hiroi15, Tatsuhiro Michikami16, Patrick Michel17, Ronald-Louis Ballouz18, Ronald-Louis Ballouz6, Olivier S. Barnouin19, Carolyn M. Ernst19, Stefan Schröder20, Hideaki Kikuchi2, Ryodo Hemmi2, Goro Komatsu1, Goro Komatsu12, T. Fukuhara5, Makoto Taguchi5, Takehiko Arai, Hiroki Senshu1, Hirohide Demura7, Yoshiko Ogawa7, Yuri Shimaki6, Tomohiko Sekiguchi21, T. G. Müller22, Axel Hagermann23, Takahide Mizuno6, Hirotomo Noda, Koji Matsumoto11, R. Yamada7, Yoshiaki Ishihara6, H. Ikeda, Hiroshi Araki, K. Yamamoto, Shinsuke Abe24, Fumi Yoshida1, A. Higuchi, Sho Sasaki25, S. Oshigami, Seiitsu Tsuruta, Kazuyoshi Asari, Seiichi Tazawa, M. Shizugami, J. Kimura25, Toshimichi Otsubo26, Hikaru Yabuta27, Sunao Hasegawa6, Masateru Ishiguro28, Shogo Tachibana2, Eric Palmer12, Robert Gaskell12, L. Le Corre12, Ralf Jaumann20, Katharina A. Otto20, Nicole Schmitz20, Paul A. Abell, M. A. Barucci29, Michael E. Zolensky, Faith Vilas12, Florian Thuillet17, C. Sugimoto2, N. Takaki2, Yutaka Suzuki2, Hiroaki Kamiyoshihara2, Masato Okada2, Kenji Nagata8, Masaki Fujimoto6, Makoto Yoshikawa11, Makoto Yoshikawa6, Yukio Yamamoto6, Yukio Yamamoto11, Kei Shirai6, Rina Noguchi6, Naoko Ogawa6, Fuyuto Terui6, Shota Kikuchi6, Tomohiro Yamaguchi6, Yusuke Oki2, Yuki Takao2, Hiroshi Takeuchi6, Go Ono, Yuya Mimasu6, Kent Yoshikawa, T. Takahashi6, Yuto Takei6, Atsushi Fujii6, Chikako Hirose, Satoru Nakazawa6, Satoshi Hosoda6, Osamu Mori6, Takanobu Shimada6, Stefania Soldini6, Takahiro Iwata6, Takahiro Iwata11, Masanao Abe11, Masanao Abe6, Hajime Yano6, Hajime Yano11, Ryudo Tsukizaki6, M. Ozaki6, M. Ozaki11, Kazutaka Nishiyama6, Takanao Saiki6, Sei-ichiro Watanabe4, Sei-ichiro Watanabe6, Yoshiyuki Tsuda11, Yoshiyuki Tsuda6 
19 Apr 2019-Science
TL;DR: Spectral observations and a principal components analysis suggest that Ryugu originates from the Eulalia or Polana asteroid family in the inner main belt, possibly via more than one generation of parent bodies.
Abstract: Additional co-authors: N Namiki, S Tanaka, Y Iijima, K Yoshioka, M Hayakawa, Y Cho, M Matsuoka, N Hirata, N Hirata, H Miyamoto, D Domingue, M Hirabayashi, T Nakamura, T Hiroi, T Michikami, P Michel, R-L Ballouz, O S Barnouin, C M Ernst, S E Schroder, H Kikuchi, R Hemmi, G Komatsu, T Fukuhara, M Taguchi, T Arai, H Senshu, H Demura, Y Ogawa, Y Shimaki, T Sekiguchi, T G Muller, T Mizuno, H Noda, K Matsumoto, R Yamada, Y Ishihara, H Ikeda, H Araki, K Yamamoto, S Abe, F Yoshida, A Higuchi, S Sasaki, S Oshigami, S Tsuruta, K Asari, S Tazawa, M Shizugami, J Kimura, T Otsubo, H Yabuta, S Hasegawa, M Ishiguro, S Tachibana, E Palmer, R Gaskell, L Le Corre, R Jaumann, K Otto, N Schmitz, P A Abell, M A Barucci, M E Zolensky, F Vilas, F Thuillet, C Sugimoto, N Takaki, Y Suzuki, H Kamiyoshihara, M Okada, K Nagata, M Fujimoto, M Yoshikawa, Y Yamamoto, K Shirai, R Noguchi, N Ogawa, F Terui, S Kikuchi, T Yamaguchi, Y Oki, Y Takao, H Takeuchi, G Ono, Y Mimasu, K Yoshikawa, T Takahashi, Y Takei, A Fujii, C Hirose, S Nakazawa, S Hosoda, O Mori, T Shimada, S Soldini, T Iwata, M Abe, H Yano, R Tsukizaki, M Ozaki, K Nishiyama, T Saiki, S Watanabe, Y Tsuda

325 citations


Cited by
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Journal ArticleDOI
14 Jul 2011-Nature
TL;DR: Simulation of the early Solar System shows how the inward migration of Jupiter to 1.5 au, and its subsequent outward migration, lead to a planetesimal disk truncated at 1’au; the terrestrial planets then form from this disk over the next 30–50 million years, with an Earth/Mars mass ratio consistent with observations.
Abstract: Jupiter and Saturn formed in a few million years from a gas-dominated protoplanetary disk, and were susceptible to gas-driven migration of their orbits on timescales of only approximately 100,000 years. Hydrodynamic simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration. The terrestrial planets finished accreting much later and their characteristics, including Mars' small mass, are best reproduced by starting from a planetesimal disk with an outer edge at about one astronomical unit from the Sun (1 AU is the Earth-Sun distance). Here we report simulations of the early Solar System that show how the inward migration of Jupiter to 1.5 AU, and its subsequent outward migration, lead to a planetesimal disk truncated at 1 AU; the terrestrial planets then form from this disk over the next 30-50 million years, with an Earth/Mars mass ratio consistent with observations. Scattering by Jupiter initially empties but then repopulates the asteroid belt, with inner-belt bodies originating between 1 and 3 AU and outer-belt bodies originating between and beyond the giant planets. This explains the significant compositional differences across the asteroid belt. The key aspect missing from previous models of terrestrial planet formation is the substantial radial migration of the giant planets, which suggests that their behaviour is more similar to that inferred for extrasolar planets than previously thought.

1,174 citations

Journal ArticleDOI
TL;DR: In this article, a review examines the experimental achievements and puts them into the context of the dust processes in protoplanetary disks, concluding that the formation of planetesimals starts with the growth of fractal dust aggregates, followed by compaction processes.
Abstract: The formation of planetesimals, the kilometer-sized planetary precursors, is still a puzzling process. Considerable progress has been made over the past years in the physical description of the first stages of planetesimal formation, owing to extensive laboratory work. This review examines the experimental achievements and puts them into the context of the dust processes in protoplanetary disks. It has become clear that planetesimal formation starts with the growth of fractal dust aggregates, followed by compaction processes. As the dust-aggregate sizes increase, the mean collision velocity also increases, leading to the stalling of the growth and possibly to fragmentation, once the dust aggregates have reached decimeter sizes. A multitude of hypotheses for the further growth have been proposed, such as very sticky materials, secondary collision processes, enhanced growth at the snow line, or cumulative dust effects with gravitational instability. We will also critically review these ideas.

892 citations

Journal ArticleDOI
15 Dec 2006-Science
TL;DR: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study, and preliminary examination shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin.
Abstract: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

886 citations

Journal ArticleDOI
02 Nov 2012-Science
TL;DR: U-corrected Pb-Pb dating from primitive meteorites indicates that chondrule formation started contemporaneously with CAIs and lasted ~3 million years, suggesting that the formation ofCAIs and chondrules reflects a process intrinsically linked to the secular evolution of accretionary disks.
Abstract: Transient heating events that formed calcium-aluminum–rich inclusions (CAIs) and chondrules are fundamental processes in the evolution of the solar protoplanetary disk, but their chronology is not understood. Using U-corrected Pb-Pb dating, we determined absolute ages of individual CAIs and chondrules from primitive meteorites. CAIs define a brief formation interval corresponding to an age of 4567.30 ± 0.16 million years (My), whereas chondrule ages range from 4567.32 ± 0.42 to 4564.71 ± 0.30 My. These data refute the long-held view of an age gap between CAIs and chondrules and, instead, indicate that chondrule formation started contemporaneously with CAIs and lasted ~3 My. This time scale is similar to disk lifetimes inferred from astronomical observations, suggesting that the formation of CAIs and chondrules reflects a process intrinsically linked to the secular evolution of accretionary disks.

724 citations