Dusty substructures induced by planets in ALMA disks: how dust growth and dynamics changes the picture

TL;DR

This study uses 2D radiation hydrodynamics simulations to explore how dust growth and dynamics influence the substructures in protoplanetary disks caused by planet formation, revealing complex dust behavior that affects observable features.

Contribution

It introduces a detailed model of dust dynamics including feedback and backreaction effects, showing their significant impact on disk substructures and providing a new tool in the PLUTO code.

Findings

Dust dynamics can alter the shape and nature of disk substructures.

Opacity feedback leads to more compact azimuthal features.

Dust feedback can produce rings instead of vortices in simulations.

Abstract

Protoplanetary disks exhibit a rich variety of substructure in millimeter continuum emission, often attributed to unseen planets. As these planets carve gaps in the gas, dust particles can accumulate in the resulting pressure bumps, forming bright features in the dust continuum. We investigate the role of dust dynamics in the gap-opening process with 2D radiation hydrodynamics simulations of planet--disk interaction and a two-population dust component modeled as a pressureless fluid. We consider the opacity feedback and backreaction due to drag forces as mm grains accumulate in pressure bumps at different stages of dust growth. We find that dust dynamics can significantly affect the resulting substructure driven by the quasi-thermal-mass planet with $M_p/M_\star=10^{-4}$. Opacity feedback causes nonaxisymmetric features to become more compact in azimuth, whereas the drag-induced backreaction tends to dissolve nonaxisymmetries. For our fiducial model, this results in multiple concentric rings of dust rather than the expected vortices and corotating dust clumps found in models without dust feedback. A higher coagulation fraction disproportionately enhances the effect of dust opacity feedback, favoring the formation of crescents rather than rings. Our results suggest that turbulent diffusion is not always necessary to explain the rarity of observed nonaxisymmetric features, and that incorporating dust dynamics is vital for interpreting the observed substructure in protoplanetary disks. We also describe and test the implementation of the publicly-available dust fluid module in the PLUTO code.