수화 소행성 류구(Ryugu)의 표토 입자가 경험한 가벼운 충격의 역사

In the present study, we investigated five Ryugu particles (A0002, A0037, C0009, C0014 and C0068) from both chambers A and C using SEM and/or TEM. The mineralogy and petrology as well as the elemental and isotopic compositions of the Ryugu particles26,27,28,29,30,31,32,33 have close similarities with the CI chondritic meteorites34,35,5 μm) components within CI-chondrites and their individual clasts: mixing of various lithologies on the CI parent body(ies). Geochemistry 79, 125532 (2019)." href="/articles/s41550-023-01947-5#ref-CR36" id="ref-link-section-d2724302e1269"36. The present study mainly focuses on the shock features of Ryugu particles observed using electron microscopy./p> σ2 ≈ σ3) using the following equation40:/p>2 GPa of pressure based on shock physics calculations (Supplementary Figs. 8–10)./p>580 °C (ref. 24). Therefore, the peak temperature constraint from Mg–Fe–serpentine is more reliable. Previous hydrocode impact simulations of serpentine-rich materials were optimized to investigate the peak pressure and peak temperature relations of both CM carbonaceous chondrites (dominated by Mg–Fe phyllosilicates) and CI chondrites46. When the shock impedance of the CI-like Ryugu materials is adapted from that of CM chondrites, the upper bound of the peak pressure for the Ryugu materials is ~5 GPa (Supplementary Fig. 4)./p>500 µm in size) rather than micrometeorites. This finding appears to be at odds with the fact that most unmelted and partially melted micrometeorites collected on the Earth's surface have genetic relationships with hydrated CI, CM, and Tagish Lake-like carbonaceous chondrites20,21. A possible explanation to reconcile this discrepancy is the breakup of hydrous meteorites due to aerodynamic heating when entering Earth’ atmosphere56,57. However, solar wind noble gases retained in most of micrometeorites58 suggest that those particles kept their original sizes when entering Earth's atmosphere./p> σ2 ≈ σ3) in the former analysis40 determined by equations (1) and (2) is comparable with peak pressure termed as the average stress ([σ1 + 2σ3]/3: σ1 > σ2 ≈ σ3) in the latter analysis62./p>4 Ga Apollo 14 and 15 zircons. Meteorit. Planet. Sci. 54, 181–201 (2018)./p>5 μm) components within CI-chondrites and their individual clasts: mixing of various lithologies on the CI parent body(ies). Geochemistry 79, 125532 (2019)./p>