Researchers have compiled a global catalog of craters on a celestial body.
A team of astronomers led by Naoyuki Hirato has created a global catalog of craters of the asteroid, the Ryuga, which allowed to determine the geological age of individual sections of its surface. It turned out that the two hemispheres Ryugu were formed at different times.
In the study, researchers used the 340 pictures that were taken at the station “Hayabusa-2” in the period from July 2018 to February 2019. Researchers analyzed the spatial arrangement of craters on Ryugu and their sizes.
As a result, scientists were able to find on the asteroid impact craters ranging in size from 10 to 20 meters. All of them on Ryugu was 77. At the same time, the researchers noticed a pattern in their distribution: in the Eastern hemisphere, close to the principal Meridian, it was found the largest number of craters, but in the Western hemisphere, there are almost no craters. This suggests that the two hemispheres of an asteroid formed at different times, in particular, that the Western hemisphere is geologically younger. In the polar regions, the Ryuga was discovered very few craters, while in lower latitudes they become more is well correlated with the processes of restructuring of the surface layer in the past.
Scientists have also found that Equatorial ridge located in the Eastern hemisphere, were formed in the distant past, when the rotation period of the asteroid was about three hours. According to the researchers, there were at least two periods in the history of Ryugu, when the speed is greatly increased.
