Presentation #202.06 in the session Asteroid Dynamics.
Tidal forces play an important role in the evolution of some Solar System bodies. Asteroids and comets can be resurfaced, stretched, reshaped, split into binary or higher multiple systems, or even destroyed by encounters with massive objects. In the context of granular environments such as those found in rubble-pile bodies, particle shape plays an important role in determining resistance to shear forces. Non-spherical constituents tend to interlock and inhibit the free deformation of a body in a manner that spherical particles cannot. Thus, we expect that rubble piles made up of irregular particles will have a higher effective shear strength and will be more difficult to disrupt. Highly elongated objects including 1I/‘Oumuamua and 2011 AG5 have prompted speculation about the origin of their shapes. It may be that the additional shear strength provided by non-spherical particles can explain how elongated objects like ‘Oumuamua and 2011 AG5 maintain shapes so far from fluid equilibrium. Much prior work has used simulation techniques to understand the effects of tidal forces on small, rubble-pile bodies. However, most studies do not directly account for the effects of constituent shape due to the technical difficulties and computational costs involved. To address this need, we have developed a new, efficient numerical method that allows us to conduct high-resolution simulations using discrete element method (DEM) simulations. In this presentation, we detail our implementation of non-spherical DEM particles in the existing pkdgrav N-body code. In addition, we will present preliminary findings on the effects of particle shape on resistance to tidal forces and on the shapes of post-disruption fragments. Initial trials suggest that rubble piles composed of non-spherical grains are more difficult to disrupt and produce more elongated fragments in the aftermath of a complete disruption. This work was supported by NASA FINESST grants No. 80NSSC20K1392 and No. 80NSSC21K1531, NASA SSERVI grant No. 80NSSC19M0216, and NSF grant No. 2108441.