An orbiter crossing an accretion disc

Abstract

We further investigate the long-term evolution of a trajectory of a stellar-mass orbiter which is gravitationally bound to a massive central body. The orbiter undergoes repetitionary collisions with an accretion disc. We consider eccentric orbits intersecting the disc once or twice per each revolution, and we solve the equations for osculating elements. We find terminal radii of the orbits and time needed to bring the orbit into the disc plane as function of initial parameters, and we show that previous simplified estimates (derived for the case of low eccentricity) remain valid within factor of two. The discussion presented in this paper offers a toy model of the orbital evolution of a satellite which passes through the rarefied gaseous environment of a stationary disc. We demonstrate that the drag on the satellite should be taken into account in calculations of the stellar distribution near the super-massive black hole in galactic centers. On the other hand, it does not impose serious restrictions on the results of gravitational wave experiments, except for the case of discs with rather high surface density.