Retention of Long-Period Gas Giant Planets: Type II Migration Revisited

Abstract

During their formation, emerging protoplanets tidally interact with their natal disks. Proto-gas-giant planets, with Hills radius larger than the disk thickness, open gaps and quench gas flow in the vicinity of their orbits. It is usually assumed that their type II migration is coupled to the viscous evolution of the disk. Although this hypothesis provides an explanation for the origin of close-in planets, it also encounter predicament on the retention of long-period orbits for most gas giant planets. Moreover, numerical simulations indicate that planets migrations are not solely determined by the viscous diffusion of their natal disk. Here we carry out a series of hydrodynamic simulations combined with analytic studies to examine the transition between different paradigms of type II migration. We find a range of planetary mass for which gas continues to flow through a severely depleted gap so that the surface density distribution in the disk region beyond the gap is maintained in a quasi-steady state. The associated gap profile modifies the location of corotation \& Lindblad resonances. In the proximity of the planet's orbit, high-order Lindblad \& corotation torque are weakened by the gas depletion in the gap while low-order Lindblad torques near the gap walls preserves their magnitude. Consequently, the intrinsic surface density distribution of the disk determines delicately both pace and direction of planets' type II migration. We show that this effect might stall the inward migration of giant planets and preserve them in disk regions where the surface density is steep.

21 pages, 12 figures, accepted by ApJ

References in corpus (17)

• The NumPy array: a structure for efficient numerical computation
• A comparative study of disc-planet interaction
• Migration and the formation of systems of hot super-Earths and Neptunes
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• Analytical protostellar disk models 1: the effect of internal dissipation and surface irradiation on the structure of disks and the location of the snow line around Sun-like stars
• Mass Estimates of a Giant Planet in a Protoplanetary Disk from the Gap Structures
• The Migration of Gap-Opening Planets is not Locked to Viscous Disk Evolution
• Migration of massive planets in accreting disks
• On corotation torques, horseshoe drag and the possibility of sustained stalled or outward protoplanetary migration
• Formation of a disc gap induced by a planet: Effect of the deviation from Keplerian disc rotation
• Type I Planet Migration in Nearly Laminar Disks
• Massive planet migration: Theoretical predictions and comparison with observations
• A Systematic Study of the Final Masses of Gas Giant Planets
• The accretion of migrating giant planets
• The End of Runaway: How Gap Opening Limits the Final Masses of Gas Giants
• The Preservation of Super Earths and the Emergence of Gas Giants after Their Progenitor Cores have Entered the Pebble Isolation Phase
• Trapping of Low-Mass Planets Outside the Truncated Inner Edges of Protoplanetary Discs