Dynamical friction on extended objects

A massive object passing through a background of non-colliding particles induces a wake of accreted matter. The gravitational effect of the wake on the object is investigated in this paper. The phase density of the background in the spherical potential of the object is derived analytically. The corresponding background response density and the force of dynamical friction over the entire extent of the object are found by numerical integration. The force field is separated into effective decelerating and deforming components. The first component is shown to be in agreement with previous results; the latter is of the same order of magnitude and might cause stripping of the object's outer parts. Tidal stripping caused by the variation of the potential of a non-homogeneous gravitationally bound background system is shown to be dominant over dynamical friction stripping.