The SOFIA Massive (SOMA) Star Formation Survey. III. From Intermediate- to High-mass Protostars
Artikel i vetenskaplig tidskrift, 2020

We present similar to 10-40 mm SOFIA-FORCAST images of 14 intermediate-mass protostar candidates as part of the SOFIA Massive (SOMA) Star Formation Survey. We build spectral energy distributions, also using archival Spitzer, Herschel, and IRAS data. We then fit the spectral energy distributions with radiative transfer models of Zhang & Tan, based on turbulent core accretion theory, to estimate key protostellar properties. With the addition of these intermediate-mass sources, based on average properties derived from SED fitting, SOMA protostars span luminosities from similar to 10(2) to 10(6) L-circle dot, current protostellar masses from similar to 0.5 to 35 M-circle dot, and ambient clump mass surface densities, Scl, from 0.1 to g cm(-2). A wide range of evolutionary states of the individual protostars and of the protocluster environments is also probed. We have also considered about 50 protostars identified in infrared dark clouds that are expected to be at the earliest stages of their evolution. With this global sample, most of the evolutionary stages of high- and intermediate-mass protostars are probed. The best-fitting models show no evidence that a threshold value of the protocluster clump mass surface density is required to form protostars up to similar to 25 M.. However, to form more massive protostars, there is tentative evidence that Sigma(cl) needs to be greater than or similar to 1 g cm(-2). We discuss how this is consistent with expectations from core accretion models that include internal feedback from the forming massive star.

Star formation


Infrared sources

Interstellar medium

Massive stars


Mengyao Liu

University of Virginia

Jonathan Tan

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

James M. De Buizer

NASA Ames Research Center

Yichen Zhang


Emily Moser

Cornell University

Maria T. Beltran

Istituto nazionale di astrofisica (INAF)

Jan E. Staff

University of The Virgin Islands


National Astronomical Observatory of Japan

Barbara Whitney

University of Wisconsin Madison

Viviana Rosero

National Radio Astronomy Observatory Socorro

Yao-Lun Yang

University of Virginia

Rubén Fedriani

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 904 1 75


Subatomär fysik

Astronomi, astrofysik och kosmologi




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