Researchers explain mineral composition variations in Ryugu asteroid samples

Universe Today reported on 2 November 2026 that scientists may have resolved a puzzling contradiction found in samples collected from the asteroid Ryugu. Scientists previously struggled to explain why fine-grained matrices within Ryugu samples and carbonaceous chondrites show widely varied compositions of clay-like minerals. The variations suggested that multiple distinct aqueous environments existed within the same parent body, an outcome that researchers considered unlikely. [1]

Asteroids are considered fossils of the early Solar System because they preserve evidence of the environmental conditions present during its formation. Unlike rocky planets, where internal processes alter rock over billions of years, primitive asteroids preserve their original chemical structures. The presence of varied mineral matrices despite this primitive state had created an ongoing scientific debate. [1]

The asteroid 162173 Ryugu is a near-Earth object measuring approximately 900 metres in diameter. It belongs to the Apollo group and is classified as a dark Cb-type asteroid. The uncrewed Japanese spacecraft Hayabusa2 arrived at Ryugu in June 2018, gathered samples, and departed in November 2019. The mission successfully delivered its sample capsule to Earth on 5 December 2020. Previous analyses of the returned Ryugu materials confirmed the presence of organic compounds, including vitamin B3 and uracil, which is one of the four base components of RNA. [4]

The new findings help refine models describing how water and minerals interacted on early planetary bodies. Resolving the contradiction allows researchers to build more accurate timelines of aqueous processes during the formation of the Solar System. [1]