Asteroid Ryugu Surface Dehydrated Due to Space Weathering

Science Society

Tokyo, Dec. 20 (Jiji Press)--A team of researchers has found that the surface of the asteroid Ryugu, from which samples were brought to Earth in 2020 by Japan's Hayabusa2 explorer, is likely to have been dehydrated due to a process called space weathering.

An initial analysis team of the Japan Aerospace Exploration Agency published the results of their analysis of the Ryugu samples in the British science journal Nature Astronomy on Tuesday.

The team focused on two findings that appeared to contradict each other: while aerial observation of the Ryugu surface by Hayabusa2 suggested the existence of only a very small amount of water, analysis of the samples brought to Earth in December 2020 found plenty of water in the interior of the minerals.

Kyoto University professor Takaaki Noguchi and others in a group within the team in charge of material analysis of Ryugu sand grains examined some 900 grains and found that around 6 pct showed signs of space weathering on their surface, through solar wind irradiation and micrometeoroid impact.

A detailed analysis of the weathered areas found that they consisted of two parts showing different types of space weathering: a smooth layer caused by solar wind irradiation and a frothy layer produced as a result of micrometeoroid impact.

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