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Characterizing the youngest Herschel-detected protostars. I. envelope structure revealed by CARMA dust continuum observations

Tobin, John, Stutz, Amelia, Megeath, S, Fischer, William, Henning, Thomas, Ragan, Sarah, Ali, Babar, Stanke, Thomas, Manoj, P, Calvet, Nuria and Hartmann, Lee 2015. Characterizing the youngest Herschel-detected protostars. I. envelope structure revealed by CARMA dust continuum observations. Astrophysical Journal 798 (2) , 128. 10.1088/0004-637X/798/2/128

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Abstract

We present Combined Array for Research in Millimeter-wave Astronomy 2.9 mm dust continuum emission observations of a sample of 14 Herschel-detected Class 0 protostars in the Orion A and B molecular clouds, drawn from the PACS Bright Red Sources (PBRS) sample. These objects are characterized by very red 24-70 μm colors and prominent submillimeter emission, suggesting that they are very young Class 0 protostars embedded in dense envelopes. We detect all of the PBRS in 2.9 mm continuum emission and emission from four protostars and one starless core in the fields toward the PBRS; we also report one new PBRS source. The ratio of 2.9 mm luminosity to bolometric luminosity is higher by a factor of ~5 on average, compared to other well-studied protostars in the Perseus and Ophiuchus clouds. The 2.9 mm visibility amplitudes for 6 of the 14 PBRS are very flat as a function of uv distance, with more than 50% of the source emission arising from radii <1500 AU. These flat visibility amplitudes are most consistent with spherically symmetric envelope density profiles with ρ vprop R -2.5. Alternatively, there could be a massive unresolved structure like a disk or a high-density inner envelope departing from a smooth power law. The large amount of mass on scales <1500 AU (implying high average central densities) leads us to suggest that that the PBRS with flat visibility amplitude profiles are the youngest PBRS and may be undergoing a brief phase of high mass infall/accretion and are possibly among the youngest Class 0 protostars. The PBRS with more rapidly declining visibility amplitudes still have large envelope masses, but could be slightly more evolved.

Item Type: Article
Date Type: Published Online
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QB Astronomy
Publisher: American Astronomical Society
ISSN: 0004-637X
Date of First Compliant Deposit: 27 November 2017
Date of Acceptance: 31 October 2014
Last Modified: 15 Mar 2019 15:37
URI: http://orca-mwe.cf.ac.uk/id/eprint/106515

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