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  • May 8, 2023
[Frontier Letter] Variations of the surface characteristics of Ryugu returned samples

The Planetary Material Sample Curation Facility3 of JAXA is responsible for initial description of valuable returned samples, publication of catalog data2, sample storage, and sample distribution to researchers worldwide. As part of curatorial works, this research is the first effort to classify Ryugu samples and describe them in detail. Based on morphological characteristics obtained by optical microscope images, 205 grains (≥1 mm) of the Ryugu samples, accounting for approximately 25% of the total weight described in the earliest six months were classified into four groups. SEM observations and X-ray diffraction analyses of representative samples of each group suggest that their characteristics may reflect differences in degree of space weathering and mineral composition. This result will help researchers to select samples from the catalog in ‘international announcement of opportunity of Hayabusa2 samples’.