Japanese space agency JAXA is exploring a distant asteroid named Ryugu with its Hayabusa 2 probe. Having arrived at its destination 200 million miles from Earth, the spacecraft managed to land on the asteroid in an incredible technical performance. Now, the first results from the study of the asteroid, with three new publications.
The first finding is that Ryugu is porous and loosely held together. It has "large-scale boulders [that] which suggest a debris pile structure," according to an article by Dr. Ing. Sei-Ichiro Watanabe of Nagoya University, Japan, and colleagues. This means that the asteroid is a collection of many smaller rocks that are bound together by gravity, with a low degree of cohesion and a high porosity.
In addition, the large boulders seen on the surface, such as the one called Otohime, indicate that these stone fragments were pulled together at Ryugu because they are too large to be formed by impacts. Overall, the asteroid has a "gyroscope" similar to another asteroid currently under investigation, Bennu.
The second study examined the surface composition of Ryugu. Using near-infrared spectroscopy, the scientists found that minerals with minerals spread on the surface. The asteroid, however, was much drier than expected.
"Just a few months after we received the first data, we have already made some exciting discoveries." Dr. Seiji Sugita, researcher at the University of Tokyo and the Chiba Institute of Technology and co-author of the three studies, told Science News. "The most important thing is the amount of water or the lack of water that Ryugu seems to possess. It is much drier than we expected, and since Ryugu is quite young at around 1
In the final study, the authors combined data from the other two newspapers to understand the origin of Ryugu. "It is estimated that small asteroids like Ryugu were born from catastrophic destruction and re-accumulation of fragments during the evolution of the solar system from much older parent bodies," the scientists told Science News. "Ryugu was probably created as a rubble that was ejected by a collision of a larger asteroid tribe."
This information not only sheds light on the composition and formation of Ryugu, but could also be used to study other asteroids such as Bennu. "That Bennu and Ryugu may be siblings, but have some strikingly different characteristics, implies that there must be many exciting and mysterious astronomical processes that we still need to explore," Sugita said.
The three publications are published in the journal Science. 19659011]