The Ryugu samples offered a unique opportunity for scientists to study material freshly gathered from an asteroid that was around 15,000,000 kilometers from Earth at the time of sampling. Surprising evidence from investigations of the samples by many research teams has suggested that Ryugu was initially formed much further from Earth, in the outer reaches of the solar system.

One of the key findings from the Tohoku University group's analysis is that the grains in the Ryugu samples were likely transported in widening circles from the inner regions of the early solar system out to the much more distant region where the original asteroid Ryugu formed. The team's conclusions are partly based on analyzing the ratio of different oxygen isotopes in the samples.

Many of the Ryugu grains were enriched in oxygen-16, which, together with analysis of the grains' sizes and mineral composition, led the researchers to suggest their ancient origin and likely transport outwards to the far regions of the solar system. The researchers want to analyze more of these oldest solar system solids in Ryugu to try to understand the mechanisms behind the radial transport outwards in the early solar nebula.

"This is fundamental research into the ancient events that built our solar system," says geochemist Daisuke Nakashima of the early Solar System Research Group at Tohoku University. Nakashima and colleagues collaborated on the investigation with researchers elsewhere in Japan and the USA. The work is part of the fascinating process of understanding how the planetary system that eventually gave rise to life on Earth was itself born.

Research Report:Chondrule-like objects and Ca-Al-rich inclusions in Ryugu may potentially be the oldest Solar System materials

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