Formation of Moons and Equatorial Ridge around Top-shaped Asteroids after Surface Landslide

Abstract Top-shaped asteroids have been observed among near-Earth asteroids. About half of them are reported to moons (on the order ?1 wt.% top-shaped primary) and many an equatorial ridge. A recent study has shown that enigmatic figure (e.g., Ryugu, Bennu, Didymos) could result from axisymmetric landslide primary during a fast spin-up near breakup rotation period. Such would inevitably form particulate disk around asteroid with short timescale (?3 hr). However, long-term full dynamical evolution is not investigated. Here, we perform continuous simulation (?700 hr) investigates sequence events surface forms evolution. We show quickly spreads produces (within ?300 The mass formed moon consistent what also demonstrate ridge naturally because fraction particles re-accretes selectively onto region primary. envision Ryugu Bennu once ancient was later lost due successive moon’s orbital Alternatively, at moon, such as Didymos, no significant occurred in its loss. Our be qualitatively applicable any rubble-pile