Curriculum Vitaes
Profile Information
- Affiliation
- Assistant Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- Degree
- 博士(工学)(東京大学)
- J-GLOBAL ID
- 200901020915152030
- researchmap Member ID
- 5000018882
Research Interests
3Research Areas
1Papers
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(14) 17-30, Feb, 2025 Peer-reviewedLead authorCorresponding author
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Journal of Evolving Space Activities, 1, Jun 12, 2023 Peer-reviewed
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Science, 379(6634), Feb 24, 2023 Peer-reviewedSamples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–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 calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <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 that Ryugu’s parent body formed ~2 million years after the beginning of Solar System formation.
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Science, 379(6634), Feb 24, 2023 Peer-reviewedThe 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.
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Science, 379(6634), Feb 24, 2023 Peer-reviewedThe near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth’s volatiles. Samples of Ryugu were retrieved by the Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in Ryugu samples and found that they are dominated by presolar and primordial components, incorporated during Solar System formation. Noble gas concentrations are higher than those in Ivuna-type carbonaceous (CI) chondrite meteorites. Several host phases of isotopically distinct nitrogen have different abundances among the samples. Our measurements support a close relationship between Ryugu and CI chondrites. Noble gases produced by galactic cosmic rays, indicating a ~5 million year exposure, and from implanted solar wind record the recent irradiation history of Ryugu after it migrated to its current orbit.
Misc.
86-
情報科学技術フォーラム講演論文集, 23rd, 2024
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電子情報通信学会大会講演論文集(CD-ROM), 2024, Mar, 2024 Lead authorCorresponding author
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宇宙科学技術連合講演会講演集(CD-ROM), 66th, 2022
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情報科学技術フォーラム講演論文集, 21st, Sep, 2022 Lead authorLast authorCorresponding author
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電子情報通信学会大会講演論文集(CD-ROM), 2022, 2022 Lead authorCorresponding author
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Aug, 2021 Lead authorLast authorCorresponding author
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Jun 21, 2021<title>Abstract</title> C-type asteroids are considered to be primitive small Solar-System bodies enriched in water and organics, providing clues for understanding the origin and evolution of the Solar System and the building blocks of life. C-type asteroid 162173 Ryugu has been characterized by remote sensing and on-asteroid measurements with Hayabusa2, but further studies are expected by direct analyses of returned samples. Here we describe the bulk sample mainly consisting of rugged and smooth particles of millimeter to submillimeter size, preserving physical and chemical properties as they were on the asteroid. The particle size distribution is found steeper than that of surface boulders11. Estimated grain densities of the samples have a peak around 1350 kg m-3, which is lower than that of meteorites suggests a high micro-porosity down to millimeter-scale, as estimated at centimeter-scale by thermal measurements. The extremely dark optical to near-infrared reflectance and the spectral profile with weak absorptions at 2.7 and 3.4 microns implying carbonaceous composition with indigenous aqueous alteration, respectively, match the global average of Ryugu, confirming the sample’s representativeness. Together with the absence of chondrule and Ca-Al-rich inclusion of larger than sub-mm, these features indicate Ryugu is most similar to CI chondrites but with darker, more porous and fragile characteristics.
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The 52nd Lunar and Planetary Science Conference(Web), Mar, 2021
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情報科学技術フォーラム講演論文集, 19th, Aug, 2020 Lead authorCorresponding author
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JpGU - AGU Joint Meeting 2020(Web), 2020, May, 2020
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2019年度 宇宙科学情報解析シンポジウム(Web), Feb, 2020 Lead authorCorresponding author
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電子情報通信学会大会講演論文集(CD-ROM), 2020, 2020 Lead authorCorresponding author
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Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx(Web), Nov, 2019
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Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx(Web), Nov, 2019
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Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx(Web), Nov, 2019
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50th Lunar and Planetary Science Conference (Web), Mar, 2019
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50th Lunar and Planetary Science Conference (Web), Mar, 2019
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平成30年度 宇宙科学情報解析シンポジウム (Web), Feb, 2019 Lead authorCorresponding author
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JpGU - AGU Joint Meeting 2019(Web), 2019, 2019
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Hayabusa Symposium 2018 (Web), Dec, 2018
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American Geophysical Union, Fall Meeting 2018, Dec, 2018
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Asia Oceania Geosciences Society 15th Annual Meeting(Web), Jun, 2018
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JpGU - AGU Joint Meeting 2018(Web), 2018, May, 2018
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JpGU - AGU Joint Meeting 2018(Web), 2018, May, 2018
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JpGU - AGU Joint Meeting 2018(Web), 2018, May, 2018
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JpGU - AGU Joint Meeting 2018(Web), 2018, May, 2018
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49th Lunar and Planetary Science Conference 2018(Web), Mar, 2018
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49th Lunar and Planetary Science Conference 2018(Web), Mar, 2018
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Journal of Spacecraft and Rockets, 55(4), 2018
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68th annual International Astronautical Congress, 10 6698-6707, 2017
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The 8th Symposium on Polar Science, 8th, 2017
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日本惑星科学会秋季講演会予稿集(Web), 2017, 2017
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Phoenix "Hayabusa": A tale of the future (13) —Landing site selection training of Hayabusa2 Mission—Planetary People - The Japanese Society for Planetary Sciences, 26(4) 139-143, 2017
Presentations
31Professional Memberships
1Research Projects
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科学研究費助成事業, 日本学術振興会, Apr, 2022 - Mar, 2025
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2018 - Mar, 2021
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2014 - Mar, 2017
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, 2010 - 2012
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2004 - 2005