Axisymmetric landslides on small planetary bodies

Abstract

We aim to understand how landslides affect the shape and rotational motion of small rubble planetary bodies. We limit ourselves to axisymmetric global landslides, and take the primordial shape of the body to also be axisymmetric. The landslides are modeled through depth-averaging, while also incorporating the effect of the body's rotation, topographical changes due to multiple landslides, the body's non-uniform gravity field and possible surface mass shedding. The body's rotational dynamics is coupled to its shape change due to landsliding, and also includes the action of radiation torque. We utilize our model to investigate regolith motion on actual asteroids. We then study the evolution of the shape and spin state of an initially spherical rubble asteroid due to impact-induced global landsliding events over its lifetime. We find that rotational fission is suppressed by regolith redistribution to the body's equator by landsliding. Furthermore, top shapes are rapidly formed and this may explain the abundance of top-shaped asteroids in near-Earth orbits.

10 pages, Submitted to JFM Rapids

References in corpus (14)

• Rubble Pile Asteroids
• Extreme Sensitivity of the YORP Effect to Small-Scale Topography
• Landslides and Mass Shedding on Spinning Spheroidal Asteroids
• Internal Structure of Asteroids Having Surface Shedding due to Rotational Instability
• Coupled Spin and Shape Evolution of Small Rubble-Pile Asteroids: Self-Limitation of the YORP Effect
• Failure modes and conditions of a cohesive, spherical body due to YORP spin-up
• Small Solar System Bodies as granular media
• Rotationally induced failure of irregularly shaped asteroids
• The Sands of Phobos: The Martian moon's eccentric orbit refreshes its surface
• Surface Motion Relative to the Irregular Celestial Bodies
• Impact Excitation of a Seismic Pulse and Vibrational Normal Modes on Asteroid Bennu and Associated Slumping of Regolith
• Stress field and spin axis relaxation for inelastic triaxial ellipsoids
• SPH Simulations for Shape Deformation of Rubble-Pile Asteroids Through Spinup: The Challenge for Making Top-Shaped Asteroids Ryugu and Bennu
• A key-formula to compute the gravitational potential of inhomogeneous discs in cylindrical coordinates