@article{2f1f2d6043964a9aa81acae727180d81,
title = "Collisional formation of top-shaped asteroids and implications for the origins of Ryugu and Bennu",
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.",
author = "P. Michel and Ballouz, {R. L.} and Barnouin, {O. S.} and M. Jutzi and Walsh, {K. J.} and May, {B. H.} and C. Manzoni and Richardson, {D. C.} and Schwartz, {S. R.} and S. Sugita and S. Watanabe and H. Miyamoto and M. Hirabayashi and Bottke, {W. F.} and Connolly, {H. C.} and M. Yoshikawa and Lauretta, {D. S.}",
note = "Funding Information: This material is based upon work supported by NASA under Contract NNM10AA11C issued through the New Frontiers Program and is also supported by JSPS International Planetary Network. P.M. acknowledges funding support from the French space agency CNES, from Academies of Excellence: Complex systems and Space, environment, risk, and resilience, part of the IDEX JEDI of the Universit{\'e} C{\^o}te d{\textquoteright}Azur and, with M.J., from the European Union{\textquoteright}s Horizon 2020 research and innovation program under grant agreement No. 870377 (project NEO-MAPP). R.L.B. acknowledges NASA grant NNH12ZDA001N, which supported development of some of the computational Methods used in this research. M.H. acknowledges NASA grant NNH17ZDA001N. We are grateful to the entire OSIRIS-REx and Hayabusa2 teams for making the encounters with Bennu and Ryugu possible. We are also extremely grateful to C.W.V. Wolner for her inputs that helped us to improve our manuscript. Simulations were run on the Bluecrab supercomputer cluster operated by the Maryland Advanced Research Computing Center under the auspices of the Johns Hopkins University and University of Maryland. Publisher Copyright: {\textcopyright} 2020, The Author(s).",
year = "2020",
month = dec,
day = "1",
doi = "10.1038/s41467-020-16433-z",
language = "English (US)",
volume = "11",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}