Formation of multiple dust rings and gaps due to intermittent planet migration in protoplanetary disks

Séminaire IPAG de Gaylor Wafflard (IPAG), jeudi 15 avril 2021, 11h00, IPAG seminar room

Recent observations of spatially resolved protoplanetary disks, in particular with the radio interferometer ALMA, reveal a large diversity of substructures in the dust thermal emission (sequences of dark rings (gaps) and bright rings, asymmetries, spirals, ...). A key challenge for protoplanetary disks and planet formation models is to be able to make a reliable connection between these observed substructures and the supposed existence of planets impacting the dust content of protoplanetary disks. The observation of N dark rings of emission is often interpreted as evidence for the presence of N planets which clear dust gaps around their orbit and form dust-trapping pressure maxima in the disk. In general, these models assume planets on fixed orbits. I choose here to take into account the gravitational interaction between a planet and the gas content of a protoplanetary disk. We will thus consider the large-scale inward migration of a single planet in a massive disk. I will present a scenario where the migration of a partial gap-opening planet with a mass comparable to Saturn is found to run away intermittently. By means of 2D gas and dust hydrodynamical simulations, I will discuss how this intermittent runaway migration can form multiple dust rings and gaps across the disk. Each time migration slows down, a pressure maximum forms beyond the planet gap and traps large dust grains. Post-processing of the simulations results with 3D dust radiative transfer calculations confirms that intermittent runaway migration can lead to the formation of multiple sets of bright and dark rings of continuum emission in the (sub)millimeter beyond the planet location.