Fast Protoplanetary Disk Modeling with DustRad: A Dust Evolution and Radiative Transfer Module for FARGO3D

We present DustRad, a dust evolution and radiative transfer module for the FARGO3D hydrodynamic code, designed to efficiently simulate key aspects of long-term protoplanetary disk evolution. The dust evolution employs a two-population scheme to track fine and coarse grains, while the radiative transfer uses a fast moment method to compute midplane heating from stellar irradiation across the disk's surface. These components are coupled with 2D vertically-averaged hydrodynamics in the r–ϕ plane and an analytic vertical (z) density profile to evaluate the radiative effects. Our tests demonstrate that the dust evolution performs comparably to previous two-population implementations in 2D hydrodynamics. We compare the radiative transfer to RadMC3D, and the temperature results agree within 15% around various substructures and shadows. With reasonable choices for the resolution of the radiative transfer, DustRad achieves run times within a factor of ten of standard 2D hydrodynamic runs with dust using the Multifluid package for FARGO3D. Applications of the module to intermediate mass planets in low-viscosity disks show inward migration can be significantly slowed with the inclusion of radiative transfer, even reversing direction for some gap-opening planets.