A Massive Protostar Forming by Ordered Collapse of a Dense, Massive Core

Type Journal Article
Names Yichen Zhang, Jonathan C. Tan, James M. De Buizer, Göran Sandell, Maria T. Beltran, Ed Churchwell, Christopher F. McKee, Ralph Shuping, Jan E. Staff, Charles Telesco, Barbara Whitney
Publication The Astrophysical Journal
Volume 767
Pages 58
Journal Abbreviation The Astrophysical Journal
Date April 1, 2013
DOI 10.1088/0004-637X/767/1/58;
ISSN 0004-637X
URL http://adsabs.harvard.edu/abs/2013ApJ...767...58Z
Library Catalog NASA ADS
Abstract We present 30 and 40 μm imaging of the massive protostar G35.20–0.74 with SOFIA-FORCAST. The high surface density of the natal core around the protostar leads to high extinction, even at these relatively long wavelengths, causing the observed flux to be dominated by that emerging from the near-facing outflow cavity. However, emission from the far-facing cavity is still clearly detected. We combine these results with fluxes from the near-infrared to mm to construct a spectral energy distribution (SED). For isotropic emission the bolometric luminosity would be 3.3 × 104 L &sun;. We perform radiative transfer modeling of a protostar forming by ordered, symmetric collapse from a massive core bounded by a clump with high-mass surface density, Σcl. To fit the SED requires protostellar masses ~20-34 M &sun; depending on the outflow cavity opening angle (35°-50°), and Σcl ~ 0.4-1 g cm–2. After accounting for the foreground extinction and the flashlight effect, the true bolometric luminosity is ~(0.7-2.2) × 105 L &sun;. One of these models also has excellent agreement with the observed intensity profiles along the outflow axis at 10, 18, 31, and 37 μm. Overall our results support a model of massive star formation involving the relatively ordered, symmetric collapse of a massive, dense core and the launching bipolar outflows that clear low-density cavities. Thus a unified model may apply for the formation of both low- and high-mass stars.
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