On the effect of chaotic orbits on dynamical friction

Chaotic orbits suffer significant changes as a result of small perturbation s. One can thus wonder whether the dynamical friction suffered by a satelli te on a regular orbit, and interacting with the stars of a galaxy, will be different if the bulk of the stars of the galaxy are in regular or chaotic orbits. In order to check that idea, we investigated the orbital decay (cau sed by dynamical friction) of a rigid satellite moving within a larger stel lar system (a galaxy) whose potential is nonintegrable. We performed numeri cal experiments using two kinds of triaxial galaxy models: (1) the triaxial generalization of Dehnen's spherical mass model (Dehnen; Merritt & Fridman ); (2) a modified Satoh model (Satoh; Carpintero, Muzzio, & Wachlin). The p ercentages of chaotic orbits present in these models were increased by pert urbing them. In the first case, a central compact object (black hole) was i ntroduced; in the second case, the perturbation was produced by allowing th e galaxy to move on a circular orbit in a logarithmic potential. The equati ons of motion were integrated with a non-self-consistent code. Our results show that the presence of chaotic orbits does not affect significantly the orbital decay of the satellite.