Asteroid Ryugu is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately 1 kilometer in diameter and is a dark object with qualities of both a C-type asteroid and a B-type asteroid. Hayabusa2, a space probe conducted by JAXA, is now on its way back to Earth with rock samples from Asteroid Ryugu.
The name refers to Ryūgū (Dragon Palace), a magical underwater palace in a Japanese folktale. In the story, the fisherman Urashima Tarō travels to the castle on the back of a turtle, and when he returns, he brings a mysterious box, much like Hayabusa2 returning with samples.
Ryugu has a diamond-shaped body and has low gravitational attraction. It was formed as part of an asteroid family whose members are likely fragments of past asteroid collisions. Ryugu contains 4400 boulders with a size larger than 5 meters.
The high number of boulders is explained with a catastrophic disruption of Ryugu’s larger parent body. The parent body of Ryugu likely experienced dehydration due to internal heating and must have formed in an environment without a strong magnetic field.
Hayabusa2 data suggest that Asteroid Ryugu sheds more light on planetary formation
The surface of the Ryugu is porous and contains no or very little dust. The meteorite’s surface heats up very quickly when exposed to sunlight, which is an indicator of low density and high porosity.
The high porosity of the boulder material showed that most meteorites originating from C-type asteroids are too fragile to survive the entry into the Earth’s atmosphere. “Fragile, highly porous asteroids like Ryugu are probably the link in the evolution of cosmic dust into massive celestial bodies,” says Matthias Grott from the DLR Institute of Planetary Research.
Hayabusa2 is a spacecraft that arrived at the asteroid In June 2018. The Japanese space agency, JAXA, operates it. It includes four rovers with various scientific instruments. On 21 September 2018, the first two of these rovers were the first successful landing on a fast-moving asteroid body.
After taking measurements and collecting samples, Hayabusa2 left Ryugu for Earth in November 2019. It is planned to return to Earth approximately 10 kilograms of soil and rock from Asteroid Ryugu by December 2020.