Collisional formation of top-shaped asteroids and implications for the origins of Ryugu and Bennu.

ABSTRACT: Asteroid shapes and hydration levels can serve as tracers of their history and origin. For instance, the asteroids (162173) Ryugu and (101955) Bennu have an oblate spheroidal shape with a pronounced equator, but contain different surface hydration levels. Here we show, through numerical simulations of large asteroid disruptions, that oblate spheroids, some of which have a pronounced equator defining a spinning top shape, can form directly through gravitational reaccumulation. We further show that rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration. The direct formation of top shapes from single disruption alone can explain the relatively old crater-retention ages of the equatorial features of Ryugu and Bennu. Two separate parent-body dis

SUBMITTER: Michel P 

PROVIDER: S-EPMC7253434 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature