Mass accretion rates in self-regulated disks of T Tauri stars

TL;DR

This study uses numerical simulations to analyze the evolution of self-regulated protostellar disks around T Tauri stars, revealing that gravitational torques drive accretion rates consistent with observations and predicting correlations with stellar and disk mass.

Contribution

It provides the first self-consistent numerical model showing how gravitational torques in self-regulated disks produce observed accretion rates and their correlations with stellar and disk mass.

Findings

Accretion rates match observed magnitudes.

Derived M_dot ∝ M_st^{1.7} correlation.

Predicted near-linear relation between disk mass and accretion rate.

Abstract

We have studied numerically the evolution of protostellar disks around intermediate and upper mass T Tauri stars (0.25 M_sun < M_st < 3.0 M_sun) that have formed self-consistently from the collapse of molecular cloud cores. In the T Tauri phase, disks settle into a self-regulated state, with low-amplitude nonaxisymmetric density perturbations persisting for at least several million years. Our main finding is that the global effect of gravitational torques due to these perturbations is to produce disk accretion rates that are of the correct magnitude to explain observed accretion onto T Tauri stars. Our models yield a correlation between accretion rate M_dot and stellar mass M_st that has a best fit M_dot \propto M_st^{1.7}, in good agreement with recent observations. We also predict a near-linear correlation between the disk accretion rate and the disk mass.