The first study of material returned to Earth from a carbon-rich asteroid dubbed Ryugu indicated that the surface is darker, porous, and more fragile.
Two studies published in Nature Astronomy describe a review of the first material brought back to Earth from a carbon-rich asteroid, Ryugu.
Carbon-rich asteroids can reveal information about the Solar System’s early past as well as the formation of organic and hydrated materials, which are the building blocks of life.
Ryugu is a one-kilometer-diamond-shaped carbon-rich near-Earth asteroid. The Hayabusa2 spacecraft returned to Earth in December 2020 with a 5.4-gram sample of material obtained from the asteroid’s surface.
Toru Yada and colleagues reveal in the first of these two studies that the Ryugu sample is extremely dark, reflecting only 2% of the light that strikes it, and has a high porosity of 46%, the highest of any meteorite investigated thus far.
In the second publication, Cédric Pilorget and colleagues determine the sample’s composition using a microscope capable of acquiring images at a range of visible and infrared light wavelengths.
The authors discover that the sample is made up of a hydrated matrix, such as clay, with organics embedded in it. Individual pieces, on the other hand, are made of various substances, such as carbonates or volatile chemicals.
These findings indicate the Ryugu samples’ microscopic diverse composition while confirming Hayabusa2’s in situ observations, implying that Ryugu is macroscopically uniform in structure and composition — similar to carbon-rich chondrite meteorites — but is darker, porous, and more fragile.
Conclusion: The contents of this sample appear to be among the most primordial material that has ever been discovered in our laboratories, forming an invaluable resource for the study of the origin and evolution of our Solar System, and serving as a model for the return of samples from other planets in the future, according to the authors.