Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface
Date
2019-03-19
Authors
Walsh, K. J.
Jawin, E. R.
Ballouz, R.-L.
Barnouin, O. S.
Bierhaus, E. B.
Connolly, H. C.
Molaro, J. L.
McCoy, T. J.
Delbo, M.
Hartzell, C. M.
Journal Title
Journal ISSN
Volume Title
Publisher
Nature Publishing Group
Abstract
Small, kilometre-sized near-Earth asteroids are expected to have young and frequently refreshed surfaces for two reasons: collisional disruptions are frequent in the main asteroid belt where they originate, and thermal or tidal processes act on them once they become near-Earth asteroids. Here we present early measurements of numerous large candidate impact craters on near-Earth asteroid (101955) Bennu by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, which indicate a surface that is between 100 million and 1 billion years old, predating Bennu's expected duration as a near-Earth asteroid. We also observe many fractured boulders, the morphology of which suggests an influence of impact or thermal processes over a considerable amount of time since the boulders were exposed at the surface. However, the surface also shows signs of more recent mass movement: clusters of boulders at topographic lows, a deficiency of small craters and infill of large craters. The oldest features likely record events from Bennu's time in the main asteroid belt.
Description
Keywords
Asteroids, comets and Kuiper belt, Early solar system, Geomorphology
Citation
Walsh, K.J., Jawin, E.R., Ballouz, R. et al. Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface. Nat. Geosci. 12, 242–246 (2019). https://doi.org/10.1038/s41561-019-0326-6
Collections
Source
Nature Geoscience
Type
Journal article
Book Title
Entity type
Access Statement
License Rights
Restricted until
2037-12-31
Downloads
File
Description