宇宙科学談話会

ISAS Space Science Colloquium & Space Science Seminar

FY2020

ENGLISH

Recent progress in the application of nucleosynthetic isotope anomalies in meteorites

YOKOYAMA Tetsuya(横山 哲也)
Tokyo Institute of Technology

Recent high precision isotope analyses of meteorites have revealed the presence of planetary-scale variabilities in isotopic compositions for a variety of elements. Some of these variations are nucleosynthetic in origin, suggesting the heterogeneous distribution of isotopically anomalous presolar components in the early Solar System. More importantly, carbonaceous chondrites (CCs) and other meteorites (noncarbonaceous meteorites; NCs) are found to form distinct clusters in the isotope spaces including ε50Ti-ε54Cr, Δ17O-ε54Cr, and ε95Mo-ε94Mo, indicating that the source materials feeding the CC and NC parent bodies were widely separated in the early Solar System. Such isotopic characteristics recorded in meteorites would reflect not only the dynamic history of material transport and mixing in the early Solar System, but also the origin of elements that were synthesized in various stellar environments before the onset of the Solar System. In this colloquium, I will present the recent progress in the application of nucleosynthetic isotope anomalies in meteorites, specifically focusing on the anomalies of trans-iron elements that were produced by the stellar nucleosynthesis of the s-, r-, and p-processes.

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ENGLISH

New insights into the Earth-Moon system revealed by KAGUYA

TERADA Kentaro(寺田 健太郎)
OSAKA University

I will present our recent new findings regarding the Earth-Moon system, revealed by the lunar orbiter KAGUYA. The first is the observation of terrestrial O+ ions around the Moon. The second topic is an asteroid shower on the Earth-Moon system 800 million years ago.

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