Three-dimensional Radiation Transfer in Young Stellar Objects

Type Journal Article
Names B. A. Whitney, T. P. Robitaille, J. E. Bjorkman, R. Dong, M. J. Wolff, K. Wood, J. Honor
Publication The Astrophysical Journal Supplement Series
Volume 207
Pages 30
Journal Abbreviation The Astrophysical Journal Supplement Series
Date August 1, 2013
DOI 10.1088/0067-0049/207/2/30;
ISSN 0067-0049
URL http://adsabs.org/2013ApJS.207.30W
Library Catalog labs.adsabs.harvard.edu
Abstract We have updated our publicly available dust radiative transfer code (HOCHUNK3D) to include new emission processes and various three-dimensional (3D) geometries appropriate for forming stars. The 3D geometries include warps and spirals in disks, accretion hotspots on the central star, fractal clumping density enhancements, and misaligned inner disks. Additional axisymmetric (2D) features include gaps in disks and envelopes, "puffed-up inner rims" in disks, multiple bipolar cavity walls, and iteration of disk vertical structure assuming hydrostatic equilibrium (HSEQ). We include the option for simple power-law envelope geometry, which, combined with fractal clumping and bipolar cavities, can be used to model evolved stars as well as protostars. We include non-thermal emission from polycyclic aromatic hydrocarbons (PAHs) and very small grains, and external illumination from the interstellar radiation field. The grid structure was modified to allow multiple dust species in each cell; based on this, a simple prescription is implemented to model dust stratification. We describe these features in detail, and show example calculations of each. Some of the more interesting results include the following: (1) outflow cavities may be more clumpy than infalling envelopes. (2) PAH emission in high-mass stars may be a better indicator of evolutionary stage than the broadband spectral energy distribution slope; and related to this, (3) externally illuminated clumps and high-mass stars in optically thin clouds can masquerade as young stellar objects. (4) Our HSEQ models suggest that dust settling is likely ubiquitous in T Tauri disks, in agreement with previous observations.
Tags DUST, Polarization, RADIATIVE TRANSFER, STARS: FORMATION, circumstellar matter, extinction, stars: pre-main sequence
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