Stellar Disruptions by Supermassive Black Holes

In this thesis I present numerical simulations of the tidal disruption of stars by supermassive black holes. These events, commonly referred to as tidal disruption events (TDEs), occur when a star passes too close to the supermassive black hole residing at the centre of a galaxy. When the star gets too close, the tidal force from the black hole is strong enough to tear the star apart into a stream of debris. Some of the debris falls back towards the black hole, forming an accretion flow that produces a luminous flare. TDEs are important astrophysical events as they have the potential to provide detailed understanding of stars and black holes in the Universe. However, to understand what we see we need detailed theoretical models that account for a variety of possible effects. In this thesis I provide new numerical simulations that explore different physical effects and the impact they have on the fallback rate and thus the lightcurves of TDEs. These include simulating spinning stars, and also simulating stars with density profiles that are taken from a stellar evolution code rather than the usual polytropic approximation. I also investigate the numerical convergence of TDE simulations with large impact parameter where the star reaches a pericentre that is much smaller than the tidal radius. These numerical simulations have advanced our understanding of the dynamics of TDEs, and will be useful for future interpretation of observational data in this area.