Header
Accueil du site > Publications > Craters, boulders and regolith of (101955) Bennu indicative of an old and (...)

Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface

Walsch, K.J. ; Jawin, E.R. ; et al. & The OSIRIS-REx Team. ; Marty, B., Nature Geosc.

Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface

Walsch, K.J. ; Jawin, E.R. ; et al. & The OSIRIS-REx Team. ; Marty, B.

Nature Geoscience, 2019, 12, 242-246

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.

Voir en ligne : https://doi.org/10.1038/s41561-019-...




publié jeudi 13 février 2020