Trajectory-Based Dust Evolution in Disks: First Results from the RAPID Simulation Code

Abstract

The rapid depletion of dust particles in protoplanetary disks limits the time available for planetesimal formation, as solids are typically accreted onto the central star before dust particles can undergo substantial growth. Dust traps formed at sharp viscosity transitions $-$ such as at the edges of the accretionally inactive dead zones $-$ can halt radial drift and enhance dust coagulation. In this study, dust dynamics is investigated using \texttt{RAPID}, a one-dimensional Lagrangian-Eulerian simulation code that tracks representative particle trajectories over time. In order to explore the effect of physical parameters on dust evolution, a grid of 243 models was run. The simulation grid covers a range of parameters such as viscosity, width of the transition region at the edges of the dead zone, disk surface density exponent, and the collisional fragmentation velocity of the dust particles. The computational domain extends from 1 to 50 AU and covers $5\times10^5$ years of disk evolution, assuming a disk mass of $\sim 0.005\,M_\odot$. The results show that pressure maxima can trap up to $3-10\,M_\oplus$ of dust, depending on the local disk conditions. However, increasing the fragmentation velocity, decreasing the viscosity, or widening the dead zone transition width tends to reduce the effectiveness of dust trapping. The simulation results with \texttt{RAPID} reveal that dust evolution is highly sensitive to the physical conditions of the disk, which governs the early stages of planetesimal growth.