Sep 23, 2022
Research results of asteroid samples collected by explorer Hayabusa2 published in ‘Science’ journal
Tohoku University, Rikkyo University and other research institutions have announced that a paper summarizing the research results of samples from the asteroid Ryugu, which were collected by Japan’s asteroid explorer Hayabusa2, has been published in the U.S. journal “Science” on September 22, 2022 (September 23, Japan time).
- how and where the parent body was formed in the solar system.
- what substances it is composed of.
- how it evolved due to subsequent chemical reactions.
- how fragments of the parent body were released.
The researchers found that Ryugu’s parent body was formed about 2 million to 3 million years after the birth of the solar system and in the outer solar system where water and carbon dioxide were present as ice. In the outer solar system, virtually all materials formed at low temperatures.
Water ice in the parent body’s interior melted due to decay heat from radioactive elements about 3 million years after its formation. The composition of anhydrous minerals then gradually changed due to water-rock chemical reactions, making the parent body’s substances mostly hydrated minerals.
The study concluded that the subsequent collision with an impactor about 1 billion years ago destroyed the parent body and that Ryugu was formed through the reassembly of fragments in a region distant from the collision point.
The results, including those from this study by the Hayabusa2 Initial Analysis Stone Team (headed by Professor Tomoki Nakamura of Tohoku University), were published in the American Association for the Advancement of Science (AAAS) journal “Science” on September 22.
Nov 30, 2023PRESS RELEASE