Simulations of Electrostatic Lofting and Subsequent Particle Motion at Bennu

Electrostatic lofting is the detachment of particles from the surface of an airless body that occurs when the electrostatic force overcomes the gravity and cohesion holding the particle on the surface. We investigate the feasibility of electrostatic lofting on Bennu using two published particle charging models and predict that 1-100 micron particles may be lofted. We then propagate the trajectories of lofted particles considering spherical gravity, solar radiation pressure and electrostatic forces. We find that, depending on particle size and lofting location, particles may experience multiple loft and reimpact events before escaping, escape directly or escape after levitating. The particle size and velocities predicted from this model are not consistent with the Bennu particle ejection event observations. Nonetheless, this model predicts that electrostatic lofting and particle loss due to solar radiation pressure are feasible on Bennu, thus contributing to the observed dearth of small particles on Bennu’s surface.