「はやぶさ」回収試料初期分析に至るまで：地球惑星物質総合解析システムの構築

抄録

We have devoted the past 25 years to the development of the Comprehensive Analytical System for Terrestrial and Extraterrestrial Materials (CASTEM), an exclusive laboratory for materials science. CASTEM facilities allow for the determination of elemental and isotopic abundances of geochemically significant elements in multi-scale ranges. CASTEM research targets are not limited to lithic rocks. We have successfully analyzed a variety of materials including human tissue. Utilizing CASTEM, we conducted the “initial analysis” of grains collected from the outermost surface of the asteroid Itokawa that were subsequently returned to Earth by the Hayabusa spacecraft. These analyses involved processing the grains, describing surface morphology, and the determination of elemental and isotopic abundances. The history of the asteroid was unveiled through comprehensive geochemical examinations of the microscopic grains suggesting a physically hostile environment at the asteroid's surface. Our results reveal that impact processes play a central role in the long-term evolution of planetary bodies in the solar system.