Iron and copper sulfides in asteroid (162173) Ryugu: Formation conditions and a comparison to the CI and CY chondritesOPEN ACCESS
C. S. Harrison, A. J. King, R. H. Jones, S. S. Russell, T. Nakamura, H. Yurimoto, T. Noguchi, R. Okazaki, H. Yabuta, H. Naraoka, K. Sakamoto, S. Tachibana, T. Yada, M. Nishimura, A. Nakato, A. Miyazaki, K. Yogata, M. Abe, T. Okada, T. Usui, M. Yoshikawa, T. Saiki, S. Tanaka, F. Terui, S. Nakazawa, S. Watanabe, Y. Tsuda
MAPS, Version of Record online: 20 January 2025
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“JAXA’s Hayabusa2 sample return mission visited the volatile-rich carbonaceous (C-type) asteroid (162173) Ryugu with the aim of ground-truthing remote observations, returning a pristine sample from a C-type asteroid, and strengthening links between asteroids and the meteorite collection. Here, we have conducted a systematic study of coarse (>10 μm) sulfide grains in Ryugu particles C0025-01 and C0103-02, the CI chondrites Orgueil and Ivuna, and the CY chondrites Y-86029 (Stage III, heated to 500–750°C) and Y-86720 (Stage IV, >750°C), using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Sulfides are sensitive tracers of secondary alteration conditions, and we find that Ryugu and the CI chondrites share a distinct sulfide assemblage that includes the iron sulfides pyrrhotite and pentlandite, and the copper sulfide cubanite, that equilibrated during periods of low temperature (~25°C) aqueous alteration. Sulfides in the CY chondrites are compositionally distinct from Ryugu and the CI chondrites as a result of post-hydration heating. However, the occurrence of Cu-rich sulfides in Ryugu, the CIs, and the CYs suggests a genetic relationship between these samples.”