The systematic gravitational drag experienced by a massive body interacting with a population of lighter bodies. In a planetesimal swarm, it tends to damp a massive embryo's random motion while transferring random kinetic energy to the smaller bodies. Its detailed strength depends on the background velocity distribution and geometry.
The stellar density and Newtonian gravitational potential perturbation induced around a moving massive object. The stellar response includes both a forced component that follows the object and switch-on collective transients. In a homogeneous stable damped model, each late-time spatial harmonic is modified by the gravitational dielectric function at the object's forcing frequency. The wake's force back on the object produces dynamical friction.
