Our goal is to describe atoms that represent element distribution of the Solar system that are continuously evolving from the beginning to the future. To understand the Solar system with spatial scale 1013 m, we analyze planetary materials that are from different origin with different processes, and determine element and isotope compositions with spatial resolution down to 10-9 m.

Planetary materials besides terrestrial ones are the rolling stones that are sampled with locality unknown. To fill the important missing information, we developed a protocol that is to determine multiple-elements, multiple-isotopes, and multiple-phases. We referred the approach to be 'comprehensive' and construct an analytical system that let us do so. The system acts as a gigantic machine with numerous instruments glued by analytical methods and disciplined people. The disciplines and samples would be taken over to the next generation to sustain our science.

We work as a team and prefer arguments scientifically.


We suggest that the rubble pile asteroid Ryugu formed through comet capture of debris and subsequent ice sublimation.


Ryugu may be the remnants of a comet, which lost its ice through sublimation as it transited into and out of the solar system. We will analyze Hayabusa2 samples to evaluate the predictions made about Ryugu in our laboratory.

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「はやぶさ 2」のタッチダウン直後に小惑星 表面から巻き上がった破片の色 (アルベド) が表裏で異なることに着目し (https://youtu.be/-3hO58HFa1M), アルベドを説明する有機物存在量を求めました.

望遠鏡と探査機による分光観測から,リュウグウが 数% の有機物を含む炭素質コンドライトに似た小惑 星だと想定されるところ,われわれの解析の結果, 有機物が総重量の六割を占めることが導かれました.

この想定をはるかに超える有機物存在量は,リュウ グウがかつて彗星だったと考える ``三朝モデル'' で説明できます.彗星が太陽近傍を周回する間に氷を 失い,有機物および岩石が濃集され,瓦礫状かつソ ロバン玉状の構造に至ったと考えられます.

三朝モデルは,「はやぶさ 2」が今年 12 月初めに持ち帰る試料を解析することに よって検証できます.「はやぶさ 2」プロジェ クトにおいて JAXA・宇宙科学研究所と連 携協定を締結した岡山大学惑星物質研究所は, フェーズ 2 キュレーション施設として初期 総合解析を担当します.

... 続きを読む


Tai Truong Nguyen, Hiroshi Kitagawa, Ivan Pineda-Velasco. Eizo Nakamura. Feedback of slab distortion on volcanic arc evolution: geochemical perspective from late Cenozoic volcanism in SW Japan, Journal of Geophysical Research: Solid Earth, (2020).

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Matin Miller, Ryoji Tanaka, Richard Greenwood. Comment on: ‘A simple cryogenic method for efficient measurement of triple oxygen isotopes in silicates’ by Ghoshmaulik et al., Rapid Communications in Mass Spectrometry, (2020).

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Li, Y-Q., Kitagawa, H., Nakamura, E., Ma, C., Hu, X., Kobayashi, K., Sakaguchi, C., Various Ages of Recycled Material in the Source of Cenozoic Basalts in Southeast China: Implications for the Role of the Hainan Plume, Journal of Petrology, 2020.

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Jan. 19, 10:00 AM in 3F Seminar Room
Seminar by Nurcan Küçükarslan

Dec. 22, 10:00 AM in 3F Seminar Room
Seminar by Dilan Madusanka Ratnayake

Dec. 8, 10:00 AM in 3F Seminar Room
Seminar by Zhang Wei

Nov. 19, 10:00 AM in 3F Seminar Room
Seminar by Havishk Tripathi

Nov. 10, 10:00 AM in 3F Seminar Room
Seminar by Tulibako Tulibonwya

Oct. 27, 10:00 AM in 3F Seminar Room
Seminar by Maya-Liliana Avramescu

Oct. 6, 10:00 AM in 3F Seminar Room
Seminar by Nghiem Van Dao