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 disruptions are not necessarily required to explain their different hydration levels.

Asteroid shapes and hydration levels can serve as tracers of their history and origin. Here, the authors show top shape asteroids can form directly through gravitational reaccumulation and rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration.

Details

Title
Collisional formation of top-shaped asteroids and implications for the origins of Ryugu and Bennu
Author
Michel, P 1   VIAFID ORCID Logo  ; R-L, Ballouz 2   VIAFID ORCID Logo  ; Barnouin, O S 3 ; Jutzi, M 4 ; Walsh, K J 5   VIAFID ORCID Logo  ; May, B H 6   VIAFID ORCID Logo  ; Manzoni, C 6   VIAFID ORCID Logo  ; Richardson, D C 7   VIAFID ORCID Logo  ; Schwartz, S R 2   VIAFID ORCID Logo  ; Sugita, S 8   VIAFID ORCID Logo  ; Watanabe, S 9   VIAFID ORCID Logo  ; Miyamoto, H 10 ; Hirabayashi, M 11   VIAFID ORCID Logo  ; Bottke, W F 5 ; Connolly, H C 12 ; Yoshikawa, M 13 ; Lauretta, D S 2 

1  Universite Côte d’Azur, Observatoire de la Côte d’Azur, Centre National de la Recherche Scientifique, Laboratoire Lagrange, Nice, France (GRID:grid.462572.0) (ISNI:0000 0004 0385 5397) 
2  University of Arizona, Lunar and Planetary Laboratory, Tucson, USA (GRID:grid.134563.6) (ISNI:0000 0001 2168 186X) 
3  The Johns Hopkins University Applied Physics Laboratory, Laurel, USA (GRID:grid.474430.0) (ISNI:0000 0004 0630 1170) 
4  University of Bern, NCCR PlanetS, Gesellsschaftsstrasse 6, 3012, Physics Institute, Bern, Switzerland (GRID:grid.5734.5) (ISNI:0000 0001 0726 5157) 
5  Southwest Research Institute, Boulder, USA (GRID:grid.201894.6) (ISNI:0000 0001 0321 4125) 
6  London Stereoscopic Company, London, UK (GRID:grid.201894.6) 
7  University of Maryland, Department of Astronomy, College Park, USA (GRID:grid.164295.d) (ISNI:0000 0001 0941 7177) 
8  School of Science, The University of Tokyo, Department of Earth and Planetary Science, Tokyo, Japan (GRID:grid.26999.3d) (ISNI:0000 0001 2151 536X) 
9  Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan (GRID:grid.27476.30) (ISNI:0000 0001 0943 978X) 
10  School of Engineering, The University of Tokyo, Department of System Innovation, Tokyo, Japan (GRID:grid.26999.3d) (ISNI:0000 0001 2151 536X) 
11  Auburn University, Department of Aerospace Engineering, Auburn, USA (GRID:grid.252546.2) (ISNI:0000 0001 2297 8753) 
12  University of Arizona, Lunar and Planetary Laboratory, Tucson, USA (GRID:grid.134563.6) (ISNI:0000 0001 2168 186X); School of Earth and Environment, Rowan University, Department of Geology, Glassboro, USA (GRID:grid.262671.6) (ISNI:0000 0000 8828 4546) 
13  JAXA, Institute of Space and Astronautical Sciences, Sagamihara, Japan (GRID:grid.62167.34) (ISNI:0000 0001 2220 7916) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41467-020-16433-z
ProQuest document ID
2407307664
Copyright
© The Author(s) 2020. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.