Thinkshop 2020

Giant planet migration (a.k.a. Type-II migration) should occur with a migration speed proportional to the disk's viscosity. This has been verified for alpha-disks with alpha>1.e-4 (Robert et al., 2018). But what happens in disks with vanishing viscosity? Does Type-II migration stalls? A variety of behaviors have been observed in the literature for migration in low-viscosity disks. Migration seems to be very stochastic, with very fast migration episodes (e.g. McNally et al., 2018). However, most simulations so far have been conducted in 2D disks. We find that low-viscosity 3D disks are much more stable than 2D disks of equivalent viscosity when they are perturbed by a planet, because they are submitted to the constraint of vertical hydrostatic equilibrium. Consequently giant planet migration in 3D disks behaves more regularly. Nevertheless, the presence of vortex formed at the outer edge of the gap opened by the planet affects the planet evolution. We have investigated in details the influence of a vortex on planet migration and on the growth of the planet's orbital eccentricity as well as the feedback of the eccentricity on migration.