Fast Protoplanetary Disk Modeling with D <scp>ust</scp> R <scp>ad</scp> : A Dust Evolution and Radiative Transfer Module for <scp>FARGO3D</scp>

Abstract We present D ust R ad , 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 R ad MC3D, and the temperature results agree within 15% around various substructures and shadows. With reasonable choices for the resolution of the radiative transfer, D ust R ad achieves run times within a factor of 10 of standard 2D hydrodynamic runs with dust using the M ultifluid 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.