On the Dust Substructures Triggered by Two Super-Earths Migrating in Low-viscosity Disks

Abstract

We investigate dust substructure formation induced by two super-Earths migrating in a low-viscosity disk with single-size dust grains selected from the submillimeter to centimeter range of sizes. The orbital evolution of planets takes place in the vicinity of the 2:1 commensurability, which allows to determine, in addition to the dust substructure properties, the dust impact on the rate of migration, the resonance capture, the libration overstability and the outcome of passage through the commensurability. Using two-dimensional two-fluid hydrodynamic simulations with dust feedback and dust diffusion taken into account, we identify two specific regions in the disk where the accumulation of dust particles is significant, leading to dust substructure formation with the dust-to-gas ratio values close to or even higher than 1 for large grains. The first region, with a narrow dust ring, is located between the planetary orbits and the second one, with a broad feature, evolving in time in a multiple ring substructure, is situated outside the orbit of the outer planet. Our results indicate that these two locations are favorable for planetesimal formation. We discuss the properties of the dust substructures formed in our simulations and outline possible consequences of their evolution for the observed architectures of multi-planetary systems.