PF-10-0017

Dusty disk winds as a variability source in structured protoplanetary disks

Scott S. Suriano, Takeru K. Suzuki, Hiroshi Kobayashi

The solid component of protoplanetary disks displays varying types of radial and azimuthal substructures. In many cases, the same disks with substructures are also observed to launch wide-angle outflows or disk winds. In all protostellar systems, photometric and spectroscopic variability is an intrinsic property. In this work, we surmise the connection between these three phenomena?disk substructure, disk winds, and protostellar variability?by analyzing the results of non-ideal 3D magnetohydrodynamic (MHD) simulations of circumstellar disks in which the processes of disk wind launching and substructure formation are inextricably linked. We first simulate the sizes of dust grains that can be entrained by a gaseous disk wind along magnetic field lines. Next, we use the resulting dust grain distributions as the input to radiative transfer simulations, from which we construct photometric light curves and near-infrared scattered light images. We find that grains with Stokes numbers less than or equal to unity in the wind region can have large enough densities in the wind to obscure the light of the central protostar over a range of wavelengths. The structured nature of the midplane dust density (seeded from the MHD simulations) results in variability due to the obscuration of the central protostar by varying amounts of dust in the high-altitude winds. For a fixed wind launching geometry, the obscuration depends on the inclination angle; a dusty disk wind observed at inclination angles between 45° and 75° could be responsible for some subset of variability in young stellar objects (i.e., dippers). Finally, we discuss the possible implications of dusty disk winds from structured disks on dust stirring and circulation, grain growth, and the planetary mass budget.

[Poster PDF File]