|
We present the results of our recent study on theinteractions between a giant planet and a self-gravitating gas disk. Weinvestigate how the disk's self-gravity affects the gap formationprocess and the migration of the giant planet.Two series of 1-D and 2-D hydrodynamic simulations are performed. Weselect several surface densities and focus on the gravitationally stableregion. To obtain more reliable gravity torques exerted on the planet, arefined treatment of disk's gravity is adopted in the vicinity of theplanet.Our results indicate that the net effect of the disk's self-gravity on thegap formation process depends on the surface density of the disk. Wenotice that there are two critical values, ∑ I and ∑II}. When the surface density of the disk is lower than the first one, ∑0< ∑I, the effect of self-gravity suppresses the formation of a gap.When∑0 > ∑I, the self-gravity of the gas tends to benefit thegap formation process and enlarge the width/depth of the gap. Accordingto our 1-D and 2-D simulations, we estimate the first critical surfacedensity ∑I ≈0.8MMSN. This effect increases until thesurface density reaches the second critical value ∑II. When ∑0 > ∑II, the gravitational turbulence in the diskbecomes dominant and the gap formation process is suppressed again. Our2-D simulations show that this critical surface density is around 3.4MMSN. We also study the associated orbital evolution of a giantplanet. Under the effect of the disk's self-gravity, the migration rateof the giant planet increases when the disk is dominated bygravitational turbulence. We show that the migration timescaleassociates with the effective viscosity and can be up to 10 4 yr. |
|
Keywords:celestial mechanics; planet formation and evolution; proto-stellar disk |
|