惑星分光観測衛星プロジェクトチーム
Profile Information
- Affiliation
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- Degree
- Doctor of Science(Mar, 1989, The University of Tokyo)
- Contact information
- yoshikawa.makoto
jaxa.jp - J-GLOBAL ID
- 200901037361657011
- researchmap Member ID
- 1000304540
Research Interests
6Research Areas
2Research History
5-
Apr, 1998 - Sep, 2003
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Apr, 1991 - Mar, 1998
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Dec, 1996 - Dec, 1997
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Apr, 1989 - Mar, 1991
Education
2-
Apr, 1984 - Mar, 1989
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Apr, 1980 - Mar, 1984
Committee Memberships
9-
Oct, 2020 - Present
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Apr, 1994 - Present
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Jan, 2013 - Mar, 2015
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Jan, 2011 - Dec, 2012
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2009 - 2011
Awards
2-
Nov, 2019
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Dec, 2018
Papers
274-
Science Advances, 10(39), Sep 27, 2024The isotopic compositions of samples returned from Cb-type asteroid Ryugu and Ivuna-type (CI) chondrites are distinct from other carbonaceous chondrites, which has led to the suggestion that Ryugu/CI chondrites formed in a different region of the accretion disk, possibly around the orbits of Uranus and Neptune. We show that, like for Fe, Ryugu and CI chondrites also have indistinguishable Ni isotope anomalies, which differ from those of other carbonaceous chondrites. We propose that this unique Fe and Ni isotopic composition reflects different accretion efficiencies of small FeNi metal grains among the carbonaceous chondrite parent bodies. The CI chondrites incorporated these grains more efficiently, possibly because they formed at the end of the disk’s lifetime, when planetesimal formation was also triggered by photoevaporation of the disk. Isotopic variations among carbonaceous chondrites may thus reflect fractionation of distinct dust components from a common reservoir, implying CI chondrites/Ryugu may have formed in the same region of the accretion disk as other carbonaceous chondrites.
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Nature Communications, 15 7488, Aug 29, 2024 Peer-reviewedAbstract Primordial carbon delivered to the early earth by asteroids and meteorites provided a diverse source of extraterrestrial organics from pre-existing simple organic compounds, complex solar-irradiated macromolecules, and macromolecules from extended hydrothermal processing. Surface regolith collected by the Hayabusa2 spacecraft from the carbon-rich asteroid 162173 Ryugu present a unique opportunity to untangle the sources and processing history of carbonaceous matter. Here we show carbonaceous grains in Ryugu can be classified into three main populations defined by spectral shape: Highly aromatic (HA), Alkyl-Aromatic (AA), and IOM-like (IL). These carbon populations may be related to primordial chemistry, since C and N isotopic compositions vary between the three groups. Diffuse carbon is occasionally dominated by molecular carbonate preferentially associated with coarse-grained phyllosilicate minerals. Compared to related carbonaceous meteorites, the greater diversity of organic functional chemistry in Ryugu indicate the pristine condition of these asteroid samples.
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Geochimica et Cosmochimica Acta, 379 172-183, Aug, 2024
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Meteoritics & Planetary Science, Jul 4, 2024
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Advances in Space Research, May, 2024
Misc.
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日本地球惑星科学連合大会予稿集(Web), 2023, 2023
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宇宙科学技術連合講演会講演集(CD-ROM), 67th, 2023
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宇宙科学技術連合講演会講演集(CD-ROM), 67th, 2023
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ASTROPHYSICAL JOURNAL LETTERS, 935(1), Aug 16, 2022We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8$^{+4.7}_{-2.6}$ ppm for O-anomalous grains, 25$^{+6}_{-5}$ ppm for SiC grains and 11$^{+5}_{-3}$ ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 $^{+7}_{-6}$ ppm SiC and 9.0$^{+5.3}_{-4.6}$ ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu-CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.
Books and Other Publications
19Presentations
32Teaching Experience
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Apr, 2019 - Present太陽と太陽系の科学 (放送大学)
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Apr, 2011 - Present位置天文学・天体力学 (東京大学)
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Apr, 2007 - Present宇宙科学 (玉川大学)
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Apr, 2006 - PresentSpace System Engineering 3 (The Graduate University for Advanced Studies)
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2006 - Present宇宙工学概論 (総合研究大学院大学)
Professional Memberships
3Research Projects
15-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2023 - Mar, 2026
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), 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, 2016 - Mar, 2019
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, 2003 - 2006
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, 2003 - 2005
