Carbonates from Ryugu: Evidence of Parent Body Aqueous Alteration in Sample A0112

Abstract

The Japanese Hayabusa2 sample return mission retrieved fragments of the near-Earth C-type car- bonaceous asteroid Ryugu 162173, that exhibit similarities in composition to the Ivuna meteorite. The high carbon content and presence of volatile-rich materials, suggests it could potentially be categorized as a primitive CI-type asteroid. [1] Among the collected samples, the piece A0112 was sent to Planetary Spectroscopy Laboratories (PSL) at the German Aerospace Center (DLR) for spectral analysis. Micro infrared spectroscopy and Raman microspectros- copy measurements were carried out on sample A0112, when the grain was still sealed within its sample holder. The analysis of the sample, allowed the determination of its bulk composition and its mineralogy under glass, without it being affected by terrestrial alteration. Carbonates could be identified, which provided significant evidence of the aqueous alteration processes that occurred in the parent body of Ryugu.