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 δ18O, Δ17O, and ε54Cr 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.
The magnetic and electronic properties of CeOInS2 and their influence on phase transition were analyzed in this study. High-temperature XRD measurements of CeOInS2 revealed that orthorhombic CeOInS2 transformed into tetragonal CeOInS2 at a high temperature of 636 K. The transport properties of CeOInS2 showed semiconducting behavior, with a larger temperature dependence of electronic resistivity in the tetragonal phase compared to that in the orthorhombic phase. Unlike structurally similar Ce(O,F)BiS2 superconductors that show long-range magnetic ordering, CeOInS2 neither exhibited superconductive transition nor long-range magnetic ordering at temperatures between 2 and 300 K.