Seminar

GJ 1148 is an M-dwarf star hosting a planetary system composed of two Saturn-mass planets in eccentric orbits with periods of 41.38 and 532.02 days. How did GJ 1148 end up with two planets that are far apart (with orbital period ratio ≈ 13) and show large eccentricity variations? The most likely scenario would be planet-planet scattering. In order to reproduce the observed system, it is likely that the initial configuration needs to have at least three planets, because dynamical instability in two-planet systems usually ends up losing one of the planets, and that the additional planet should be comparable in mass to the other two to produce sufficiently large eccentricities. We are performing a set of N-body simulations, with three giant planets that are separated by a few mutual Hill radii. We will examine the outcome and adjust the initial conditions to determine the configuration (orbital separation and planetary masses) that are more likely to result in the observed GJ 1148 system. If this scenario is successful, it would imply that there was yet another giant planet in the original GJ 1148 system.

Additional information: Mr. Longhui YUAN, yuanlh@connect.hku.hk