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2C-O1-0900 PDF
はやぶさ２探査機の回収した小惑星リュウグウ試料の揮発性成分
The Hayabusa2 spacecraft was launched in 2014 to a near-Earth asteroid (162173) The solid Ryugu samples were transported to the JAXA curation facility and subjected to initial observations in clean chambers at JAXA. About 6% of the total mass of the returned samples was allocated to 6 sub-teams of the Hayabusa2-Initial-Analysis in June 2021. The Ryugu grains are mainly composed of fine-grained phyllosilicates, accompanied with carbonates, magnetites, and sulfides. The abundances and isotopic compositions of the major elements show close similarities with those of CI chondrites. Compared with primitive meteorites collected on the Earth, the Ryugu samples are the most enriched in primordial noble gas components, which are thought to have been carried by solar-system carbonaceous materials and presolar grains formed before the birth of the Sun. These results suggest that the Ryugu material is one of the most primitive materials in the solar system.