Bennu Asteroid

Anny Chantal Levasseur-Regourd (1)

1 PLANETO - LATMOS

(101955) Bennu is a near-Earth carbonaceous asteroid, suggested to belong to the taxonomic class B or more likely to the rare class F (Belskaya et al. 2005) from its spectro-polarimetric properties (Cellino et al. 2018). It has been the target of the NASA OSIRIS-REx sample return mission, which rendezvoused with it in late 2018 and collected samples in 2020. The return capsule should reach Earth in September 2023 and allow detailed analyses of the samples, as well as comparisons with those returned from asteroid Ryugu. Bennu is (like asteroids Steins and Ryugu) a roundish, diamond-shaped body with an equatorial bulge, probably formed by re-accumulation of rubble ejected after catastrophic disruption of a larger parent body. Its mean size is ≈490 m, and its rotation period ≈4.3 h. Its low density (≈1190 kg m−3) suggests a huge bulk porosity, as expected for a “rubble-pile” asteroid (Barnouin et al. 2019). Its surface gravity is thus extremely low,...

Domains: Earth and Planetary Astrophysics [astro-ph.EP]

Anny Chantal Levasseur-Regourd. Bennu Asteroid. Encyclopedia of Astrobiology, Springer Berlin Heidelberg, 2022, 978-3-642-27833-4. ⟨10.1007/978-3-642-27833-4_5564-1⟩. ⟨insu-03475935⟩