In recent years the existence of massive black holes (MBHs) in the centres of galaxies has moved from being theoretically possible to almost certain. However the masses of these MBHs appear to have become very large very quickly. In many cases they need to accrete the mass of the sun every year, right from the earliest phases of galaxy formation. The aim of the StarDisk project is to examine the interaction between stars and the gas in the accretion disk around the MBH. The image on the right shows the conditions in an active galactic centre, with stars being represented by white points and the gas in the x-y plane by orange blobs.

Each time the star crosses the disk a small amount of energy is transferred to the disk, thus decaying the orbit of the star and ensuring further passages. A schematic of this process is shown to the left where each time the star (red circle) crosses the accretion disk then a velocity impulse is given to the star opposing its motion.

This process continues until the star is brought into the centre of the accretion disk, and encounters the central massive black hole (MBH). The snapshot from the movie below is shown on the right where the target star is shown in green and the MBH in purple.

This target star began in the outer regions of the star cluster centred on the MBH (top-right image). After awhile it crossed the disk sufficiently often to visibly decay the orbit, eventually ending up consumed by the MBH (right).