By examining samples from asteroid Ryugu, scientists have made the initial discovery. They have found tiny particles of ancient matter that are even older than our solar system. Located in Earth’s near-solar orbit, the Ryugu asteroid resembles a spinning top and orbits the Sun every 16 months. The Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 spacecraft was tasked with finding asteroid Ryugu (162173) from June 2018 to November 2019. Sending a series of landers and probes, the spacecraft collected a sample from Ryugu and sent it back to Earth. 2020. In a new analysis of this sample, scientists have discovered pre-solar material in it and believe that studying it may shed some new light on the events behind the formation of our solar system.
According to Jens Barosz, a cosmochemist at the Carnegie Institution of Washington, different types of presolar grains are the result of different types of stars and stellar processes. These can be identified using their isotopic signature, he added. Isotopes are considered important for understanding the chemistry of distant stars and the processes that occur within them.
“The opportunity to identify and study these grains in the lab could help us understand the astrophysical events that shaped our solar system, as well as other cosmic objects,” said Barosh. He is also the lead author of the study.
In a study published in Astrophysical Journal Letters, the team was able to detect 57 grains of presolar material. Previous studies also found some presolar material in Ryugu. The team compared the newly discovered grains to those found in meteorites and found that Ryugu had a similar composition to CI chondrites. These are a rare sub-type of carbonaceous chondrites, which have a similar structure to the Sun.
“Samples returned from asteroid Ryugu by the Hayabusa2 spacecraft contain grains of presolar stardust. Their abundance and composition are similar to those of presolar material found in CI chondrites,” the researchers wrote in their paper. They added that the results provide evidence that asteroid Ryugu is closely related to chondrites.