| 研究実績の概要 |
To constrain the distribution of water and organics in the early solar system, we have measured the hydrogen isotope composition of a series of primitive meteorites (chondrites). The secondary ion mass spectrometer IMS1280HR at Hokkaido University was used to look at the relationship between organics and hydrated minerals in chondrite matrices. CM-type carbonaceous chondrites were chosen for their wide range of asteroidal hydrothermalism degree and for their high content of water and organics.
We found that, at a scale of tens of micrometers, most of the CM chondrite matrices correspond to a mixture of two H-bearing phases: a D-rich OM with a D-poor water. Nonetheless, the least altered chondrite Paris shows the presence of a third component that might be a D-richer ice or some pre-accretionally hydrated inorganic phases. These results give new constraints on the evolution of water on asteroids and on its distribution in the early solar system.
The first results have been presented in three international meetings in Japan and in the United States (Solar System Symposium, Goldschmidt conference and LPSC) and are the object of a paper in preparation. Most recent results on organics in meteorites will be the object of a second paper to be published in 2017.
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