| Project/Area Number |
22K18725
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 17:Earth and planetary science and related fields
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
石田 章純 東北大学, 理学研究科, 助教 (10633638)
高柳 栄子 東北大学, 理学研究科, 准教授 (40729208)
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| Project Period (FY) |
2022-06-30 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2023: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2022: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | 炭酸塩 / 隕石 / 炭素同位体 / ホルモース反応 |
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| Outline of Research at the Start |
炭素質隕石には小惑星中の水熱反応で形成されたと考えられている13Cに富む炭酸塩が含まれている。この成因の一部は極低温環境で固化したドライアイスであったと推察されているが、それだけでは説明がつかない。本研究では、炭素質小惑星内部で起こり得る、ホルモース型反応で、13Cに富む炭酸塩が形成されるかどうか、生成する炭素同位体組成は隕石中の炭酸塩に相当するものかどうかを明らかにする。
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| Outline of Final Research Achievements |
Aqueously-altered meteorites and asteroids contain organic matter such as amino acids and sugars, which may have contributed to the supply of life's building blocks to the Earth. Such meteorites also contain carbonates with a wide range of carbon isotopic compositions enriched in 13C. In this study, we focused on the fact that formose-type reactions using aldehydes as a carbon source produce amino acids and sugars, and that these reactions are catalyzed by calcium.
Various Formose-type reaction experiments were performed to identify the carbonates produced. The results showed that the carbonate produced was calcite, and that the calcite carbon was enriched in 13C compared to the insoluble organic matter produced at the same time. On the other hand, the extent of 13C enrichment is not enough to explain the wide range of 13C-rich carbon isotopic compositions found in the meteorites. Mixing with highly 13C enriched CO2 in asteroids may explain the wide range of 13C enrichments.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では隕石や小惑星に含まれる炭素の形態の形態の一つである炭酸塩の起源に関して、新たな説を提供し、その説によって生成する炭酸塩の炭素同位体組成を制約した。その結果、この炭素源の寄与はありうるが、全てがこの起源では説明できないことが明らかになった。
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