Star-disc interactions near a massive black hole

We examine the possibility that stars in the nuclei of galaxies could be ground down into short-period orbits, by interaction with a disc around a central massive black hole. A star on a highly eccentric orbit, which passed close to the hole, would lose energy and momentum in passing through the disc. The cumulative effect of many passages would bring the star into a circular orbit corotating with the disc. The star would then either open up a gap in the disc (if the disc is thinner than the star's Roche radius and the viscosity in the disc is sufficiently low), or accrete material from the disc.