Rotational Failure of Rubble-pile Bodies: Influences of Shear and Cohesive Strengths
Richardson, Derek C.
Barnouin, Olivier S.
Schwartz, Stephen R.
AffiliationUniv Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationThe Astrophysical Journal, 857:15 (20pp), 2018 April 10
Rights© 2018. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractThe shear and cohesive strengths of a rubble-pile asteroid could influence the critical spin at which the body fails and its subsequent evolution. We present results using a soft-sphere discrete element method to explore the mechanical properties and dynamical behaviors of self-gravitating rubble piles experiencing increasing rotational centrifugal forces. A comprehensive contact model incorporating translational and rotational friction and van der Waals cohesive interactions is developed to simulate rubble-pile asteroids. It is observed that the critical spin depends strongly on both the frictional and cohesive forces between particles in contact; however, the failure behaviors only show dependence on the cohesive force. As cohesion increases, the deformation of the simulated body prior to disruption is diminished, the disruption process is more abrupt, and the component size of the fissioned material is increased. When the cohesive strength is high enough, the body can disaggregate into similar-size fragments, which could be a plausible mechanism to form asteroid pairs or active asteroids. The size distribution and velocity dispersion of the fragments in high-cohesion simulations show similarities to the disintegrating asteroid P/2013 R3, indicating that this asteroid may possess comparable cohesion in its structure and experience rotational fission in a similar manner. Additionally, we propose a method for estimating a rubble pile's friction angle and bulk cohesion from spin-up numerical experiments, which provides the opportunity for making quantitative comparisons with continuum theory. The results show that the present technique has great potential for predicting the behaviors and estimating the material strengths of cohesive rubble-pile asteroids.
VersionFinal published version
SponsorsNASA - Solar System Workings program [NNX15AH90G]; National Natural Science Foundation of China ; NASA Double Asteroid Redirection Test (DART); French space agency CNES [OSIRIS-REx/BCU62, Hayabusa2/BCU66]; European Space Agency; Academy of Excellence: Complex systems and Space, IDEX JEDI of the Universite Cote d'Azur; Academy of Excellence: environment, risk, and resilience, IDEX JEDI of the Universite Cote d'Azur; Center for Planetary Origins (C4PO)