Analysis of "Stone" Samples from C-Type Asteroid Ryugu
As a part of activities of initial analysis, we analyzed eighteen Ryugu “stone” samples of 1 ~ 8mm in size: seven stones from the 1st touch down site and eleven from the 2nd touch down site. Ryugu stones were analyzed first using X-rays, UV, visible, near-infrared, mid-infrared, and muon probes for surface reflectance spectra, internal 3D structure and element distribution, crystal structures, and bulk composition of light elements such as C, N, and O. Measurements for magnetic, thermal, and physical properties using some stones were also performed. TOF-SIMS analysis of fluid inclusions as being continued. Small particles separated from some stones were analyzed by IR-CT. Based on 3D-CT images of individual stones, objects of interests were identified, separated by pFIB cutting, and exposed by polishing on the surface of epoxy disks. FE-EPMA/FE-SEM analysis was made on ~40 polished epoxy disks for chemical composition and textural observation. FIB sections and small (~15 μm in size) fragments were separated from polished surface and analyzed by TEM, STXM,XRF, and nano-CT.