Alignment of fractures on Bennu’s boulders indicative of rapid asteroid surface evolution

Autor: Marco Delbo, Kevin J. Walsh, Christophe Matonti, Justin Wilkerson, Maurizio Pajola, Manar M. Al Asad, Chrysa Avdellidou, Ronald-Louis Ballouz, Carina A. Bennett, Harold C. Connolly, Daniella N. DellaGiustina, Dathon R. Golish, Jamie L. Molaro, Bashar Rizk, Stephen R. Schwartz, Dante S. Lauretta
Přispěvatelé: Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), University of British Columbia (UBC), University of Arizona, Planetary Science Institute [Tucson] (PSI), ANR-18-CE31-0014,ORIGINS,A la recherche des planétésimaux de notre système solaire(2018)
Rok vydání: 2022
Předmět:
Zdroj: Nature Geoscience
Nature Geoscience, 2022, 15, pp.453-457. ⟨10.1038/s41561-022-00940-3⟩
ISSN: 1752-0908
1752-0894
Popis: International audience; On asteroids, fractures develop due to stresses driven by diurnal temperature variations at spatial scales ranging from sub-millimetres to metres. However, the timescales of such rock fracturing by thermal fatigue are poorly constrained by observations. Here we analyse images of the asteroid (101955) Bennu obtained by the Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) mission and show that metre-scale fractures on the boulders exposed at the surface have a preferential meridional orientation, consistent with cracking induced by diurnal temperature variations. Using an analytical model of fracture propagation, we suggest that fractures the length of those on Bennu’s boulders can be produced in 104–105 years. This is a comparable or shorter timescale than mass movement processes that act to expose fresh surfaces and reorient boulders and any preferential direction signature. We propose that boulder surface fracturing happens rapidly compared with the lifetime in near-Earth space of Bennu and other carbonaceous asteroids. The damage due to this space-weathering process has consequences for the material properties of these asteroids, with implications for the preservation of the primordial signature acquired during the accretional phases in the protoplanetary disk of our solar system.
Databáze: OpenAIRE
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