This movie below is of one of the simulations presented in Dunhill & Stamatellos (MNRAS, submitted). Using 3D SPH simulations we studied the interaction between young giant planets and gravitationally unstable discs using the β-cooling prescription. We find that the planet is quickly driven eccentric as it interacts with turbulent structures in the disc. This provides an effective method for seeding an initial non-zero eccentricity. Goldreich & Sari (2003) and Duffell & Chiang (2015) both independently found that further eccentricity growth by disc torques is made possible if the planet is initially eccentric. These results combined suggest that there may be a difference in the final eccentricity distribution for planets formed by gravitational fragmentation from those formed by core accretion.

The movie below shows a comparison between the β = 10 (left) and β = 25 (right) run, demonstrating that faster cooling (lower β) discs with more pronounced GI structures are more efficient at growing the eccentricity. In each case we start at tβ orbits as the planet is kept on a fixed circular orbit until this time. The movie was rendered using SPLASH