Effect of Irregular Particle Shape in Simulations of Tidal Disruption and Reaccumulation of Small Solar System Bodies

Abstract Small solar system bodies subjected to planetary tides may be resurfaced, distorted, reshaped, split into binary or higher-multiple systems, or fragmented entirely. We investigate the effects of particle shape on numerical models of tidal deformation and disruption using an N -body code equipped with soft-sphere particle contacts to carry out tidal encounters between the Earth and small rubble-pile bodies. This work uses a “glued-sphere” method in which numerous spherical particles are glued into rigid aggregates to represent irregular particle shapes, and accounts for both gravitational and contact torques. We compare the results of tidal encounters between the Earth and rubble-pile bodies with differently shaped constituents and varying resolutions. In our simulations, tidally induced mass loss shows that postdisruption rubble-pile remnants made up of nonspherical particles may retain up to ∼50% more mass than those composed of spheres. Nonspherical particles can also reduce the number of fragments produced by tidal disruption by up to ∼50% compared to simulations with spherical particles. We find little effect on the mass of satellites around the largest disruption remnants. Particle shape also appears to have little to no impact on the elongation of postdisruption remnants. The magnitude of these effects varies considerably depending on the specific shapes in question, and there are trends of decreasing effect with increasing simulation resolution. Overall, we find that particle shape can significantly alter the number and mass of fragments in tidal disruption simulations and should be considered an important factor in studies of rubble-pile tidal processes.