Hayabusa2 Touchdown Finds Evidence Asteroid Ryugu Visited Sun

Category: Cover Story

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Asteroid 162173 Ryugu, visited by the Japan Aerospace Exploration Agency (JAXA) Hayabusa2 mission, shows evidence for having previously experienced  excursions closer to the Sun than its current orbital position. 

Hayabusa2 collected samples from Ryugu’s surface on Feb. 21, 2019. Images from the spacecraft during the sample collection showed Hayabusa2’s thrusters disturbed dark, fine grains from redder materials. The spectroscopic and color properties across Ryugu, over various latitudes, suggest that Ryugu’s surface has been processed by solar heating and/or space-weathering. These processes reddening the surface. Examination of the sample collection site suggests that surface reddening occurred over a short period of time, supporting the hypothesis that Ryugu, at one time, orbited closer to the Sun. 

PSI’s Deborah Domingue has supported mission team members and provided photometric characterization of the surface of 162173 Ryugu. Her studies provided one of many inputs into the Team’s selection of the first sample collection site. The analysis and characterization of the sample site after the sample acquisition is the subject of a recently published article in the journal Science, of which Domingue is a co-author. 

PSI’s Lucille Le Corre is also working on the Hayabusa2 mission.