Simulations of gaseous disc-embedded planet interaction

We present global three-dimensional self-gravitating smoothed particle hydrodynamics (SPH) simulations of an isothermal gaseous disc interacting with an embedded planet. Discs of varying stability are simulated with planets ranging from 10 Earth masses to 2 Jupiter masses. The SPH technique provides the large dynamic range needed to accurately capture the large-scale behaviour of the disc and the small-scale interaction of the planet with surrounding material. Most runs used 105 gas particles, giving us the spatial resolution required to observe the formation of planets. We find four regions in parameter space: low-mass planets undergo type I migration; higher-mass planets can form a gap; the gravitational instability mode of planet formation in marginally stable discs can be triggered by embedded planets; discs that are completely unstable can fragment to form many planets. The disc stability is the most important factor in determining which interaction a system will exhibit. For the stable disc cases, our migration and accretion time-scales are shorter and scale differently from previously suggested.