On the orbital evolution of a giant planet pair embedded in a gaseous disk. I: Jupiter-Saturn configuration

TL;DR

This study uses high-resolution hydrodynamical simulations to explore how Jupiter and Saturn's orbits evolve within a gaseous disk, revealing how disk density profiles influence their migration, resonance trapping, and stability, informing Solar System formation models.

Contribution

The paper extends previous work by analyzing the effects of different surface density profiles on the orbital migration and resonance capture of Jupiter and Saturn in a gaseous disk.

Findings

Migration rate increases with surface density profile index α.

Jupiter and Saturn are trapped in 2:1 or 3:2 mean motion resonances depending on α.

High eccentricity of Saturn destabilizes the 3:2 resonance.

Abstract

We carry out a series of high resolution ($1024\times 1024$) hydrodynamical simulations to investigate the orbital evolution of Jupiter and Saturn embedded in a gaseous protostellar disk. Our work extends the results in the classical papers of Masset & Snellgrove (2001) and Morbidelli & Crida (2007) by exploring various surface density profiles ($\sigma$), where $\sigma \propto r^{-\alpha}$. The stability of the mean motion resonances(MMRs) caused by the convergent migration of the two planets is studied as well. Our results show that:(1) The gap formation process of Saturn is greatly delayed by the tidal perturbation of Jupiter. These perturbations cause inward or outward runaway migration of Saturn, depending on the density profiles on the disk. (2) The convergent migration rate increases as $\alpha$ increases and the type of MMRs depends on $\alpha$ as well. When $0<\alpha<1$, the convergent migration speed of Jupiter and Saturn is relatively slow, thus they are trapped into 2:1 MMR. When $\alpha>4/3$, Saturn passes through the $2:1$ MMR with Jupiter and is captured into the $3:2$ MMR. (3) The $3:2$ MMR turns out to be unstable when the eccentricity of Saturn ($e_s$) increases too high. The critical value above which instability will set in is $e_s \sim 0.15$. We also observe that the two planets are trapped into $2:1$ MMR after the break of $3:2$ MMR. This process may provide useful information for the formation of orbital configuration between Jupiter and Saturn in the Solar System.