Asteroid Ryugu Likely Orbited between Sun, Mercury: Study

Science Society Technology

Tokyo, May 8 (Jiji Press)--Asteroid Ryugu is likely to have been briefly on an orbit long ago that took it closer to the sun than Mercury was, a Japanese research team has said.

Temperatures are believed to have reached 600 to 800 degrees Celsius at that time on the surface of the asteroid, probed by Japan's Hayabusa2 unmanned spacecraft, according to a study by the team published Friday on the online edition of the U.S. journal Science.

The team, including the Japan Aerospace Exploration Agency (JAXA) and the University of Tokyo, made the discovery by examining close-up images captured when Hayabusa2 carried out its first landing on the asteroid to collect samples in February last year.

The analysis of images of the entire asteroid mainly by University of Tokyo researchers Tomokatsu Morota and Seiji Sugita showed that the surface of mid-latitude regions was more altered, mainly because of heating, while the surface of the polar regions and the top layer inside new craters were less altered.

From images taken immediately after the touchdown, it was also learned that clouds of sand raised by Hayabusa2 were altered particles, which thinly covered the surface of rocks on Ryugu.

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