The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University.
Department of Information and Basic Science, Nagoya City University.
Proc Jpn Acad Ser B Phys Biol Sci. 2022;98(6):227-282. doi: 10.2183/pjab.98.015.
Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δO, ΔO, and εCr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10's of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation.
这里呈现的是隼鸟 2 号任务从 C 型小行星龙宫带回的 16 个代表性颗粒的综合分析结果。龙宫颗粒的平均组成包括 50%的层状硅酸盐基质、41%的孔隙率和 9%的次要相，包括有机物。颗粒中 70 种元素的丰度与 CI 球粒陨石非常接近。龙宫颗粒的整体 δO、ΔO 和 εCr 值均高于 CI 球粒陨石。因此，龙宫采集了最原始、受热处理最少的原太阳星云储层。这一发现与多尺度 H-C-N 同位素组成一致，表明龙宫有机物的起源既在原太阳星云内，也在星际介质内。这里获得的分析数据表明，在龙宫母体行星形成后几亿年（<260 万年），水蚀变过程中形成了复杂的可溶性有机物。随后，龙宫母体行星发生碎裂，通过升华演变成当前的小行星龙宫。
Zotero 插件
