Dispersal of protoplanetary disks by central wind stripping

TL;DR

This paper models how winds from the central star or disk strip away protoplanetary disks, showing that wind stripping can dominate disk dispersal under specific low-accretion conditions.

Contribution

It introduces a new model for disk dispersal via wind stripping, quantifying the process and comparing its significance to photoevaporation and viscous evolution.

Findings

Dispersal time at 1 AU is ~6 Myr with specified parameters.

Wind stripping can dominate disk dispersal for low accretion rates.

Entrainment efficiency of ~10% of sound speed is a key factor.

Abstract

We present a model for the dispersal of protoplanetary disks by winds from either the central star or the inner disk. These winds obliquely strike the flaring disk surface and strip away disk material by entraining it in an outward radial-moving flow at the wind-disk interface which lies several disk scale heights above the mid-plane. The disk dispersal time depends on the entrainment velocity at which disk material flows into this turbulent shear layer interface. If the entrainment efficiency is ~10% of the local sound speed, a likely upper limit, the dispersal time at 1 AU is ~6 Myr for a disk with a surface density of 10^3 g cm^{-2}, a solar mass central star, and a wind with an outflow rate 10^{-8} Msun/yr and terminal velocity 200 km/s. When compared to photoevaporation and viscous evolution, wind stripping can be a dominant mechanism only for the combination of low accretion rates (< 10^{-8} Msun/yr) and wind outflow rates approaching these accretion rates. This case is unusual since generally outflow rates are < 0.1 of of accretion rates.