Ryugu
A dark, carbon-rich near-Earth asteroid shaped like a spinning top, sampled by Japan's Hayabusa2 mission.
Ryugu (asteroid 162173) is about 900 metres across, with a pronounced ridge around its equator that gives it a spinning-top or diamond shape. It is one of the darkest objects ever visited, reflecting only a few per cent of the light that hits it. JAXA's Hayabusa2 spacecraft arrived in June 2018, released small hopping rovers and a lander, and touched down twice to collect material. In April 2019 it fired a copper projectile into the surface to make an artificial crater and expose fresher material below.
The capsule landed in Australia in December 2020 with about 5.4 grams of sample. Laboratory work showed Ryugu is made of material very similar to CI chondrites, the rarest and most chemically primitive meteorite group, rich in clay minerals, carbonates, magnetite and organic compounds. Because the samples never passed through Earth's atmosphere or sat in our wet environment, they are cleaner than any CI meteorite and include delicate salts and organic molecules, among them the nucleobase uracil.
The comparison meteorite is Orgueil, which fell in France in 1864. Like Ryugu, it is black, crumbly and very light for its size.
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