Heterogeneous mass distribution of the rubble-pile asteroid (101955) Bennu
- Creators
- Scheeres, D.
- French, A.
- Tricarico, P.
- Chesley, S.
- Takahashi, Y.
- Farnocchia, D.
- Mcmahon, J.
- Brack, D.
- Davis, A.
- Ballouz, R.-L.
- Jawin, E.
- Rozitis, B.
- Emery, J.
- Ryan, A.
- Park, R.
- Rush, B.
- Mastrodemos, N.
- Kennedy, B.
- Bellerose, J.
- Lubey, D.
- Velez, D.
- Vaughan, A.
- Leonard, J M
- Geeraert, J.
- Page, B.
- Antreasian, P.
- Mazarico, E.
- Getzandanner, K.
- Rowlands, D.
- Moreau, M.
- Small, J.
- Highsmith, D.
- Goossens, S.
- Palmer, E.
- Weirich, J.
- Gaskell, R.
- Barnouin, Olivier
- Daly, M.
- Seabrook, J.
- Al Asad, M.
- Philpott, L.
- Johnson, C.
- Hartzell, C.
- Hamilton, V.
- Michel, Patrick
- Walsh, K.
- Nolan, M.
- Lauretta, D.
Description
The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the gravity field of the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling the spacecraft in orbit about the asteroid and (ii) tracking and modeling pebble-sized particles naturally ejected from Bennu's surface into sustained orbits. These approaches yield statistically consistent results up to degree and order 3, with the particle-based field being statistically significant up to degree and order 9. Comparisons with a constant-density shape model show that Bennu has a heterogeneous mass distribution. These deviations can be modeled with lower densities at Bennu's equatorial bulge and center. The lower-density equator is consistent with recent migration and redistribution of material. The lower-density center is consistent with a past period of rapid rotation, either from a previous Yarkovsky-O'Keefe-Radzievskii-Paddack cycle or arising during Bennu's accretion following the disruption of its parent body.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-03059238
- URN
- urn:oai:HAL:hal-03059238v1
- Origin repository
- UNICA