Speaker
Description
The migration of low-mass planets is governed by the interplay between gravitational torques from the gaseous and solid components of the protoplanetary disc. Performing 2D global hydrodynamic simulations in locally isothermal discs, we investigate the often-neglected back-reaction of solid material on gas dynamics across varying metallicities, Stokes numbers, and accretion efficiencies. Our results demonstrate that the combined effect of back-reaction and planetary accretion frequently flips total torques from negative to positive, particularly for Earth-sized embryos. To validate these findings, we performed simulations using Adaptive Mesh Refinement (AMR) to allow for self-consistent migration tracks. The observed changes in migration behaviour show qualitative agreement with our calculated torque trends. In metal-rich discs, standard linear scaling prescriptions fail for weakly coupled solid species, as feedback-driven gas perturbations in the co-orbital region heavily modify the gas torques. We conclude that including solid back-reaction is essential for accurate migration modelling.