Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites
Description
Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37 degrees +/- 10 degrees C, about 5.2(-0.7)(+0.8) million (statistical) or 5.2(-2.1)(+1.6) million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above similar to 100 degrees C. The samples have a chemical composition that more closely resembles that of the Sun's photosphere than other natural samples do.
Journal
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- Science
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Science 379 (6634), 786-+, 2023
The American Association for the Advancement of Science（AAAS）
