Johnston, KG, Robitaille, TP, Beuther, H et al. (6 more authors) (2015) A Keplerian-like disk around the forming O-type star AFGL 4176. Astrophysical Journal Letters, 813 (1). L19. ISSN 2041-8205
Abstract
We present Atacama Large Millimeter/submillimeter Array (ALMA) line and continuum observa- tions at 1.2mm with 0.3′′ resolution that uncover a Keplerian-like disk around the forming O-type star AFGL 4176. The continuum emission from the disk at 1.21mm (source mm1) has a deconvolved size of 870±110AU × 330±300AU and arises from a structure 8M⊙ in mass, calculated assuming a dust temperature of 190K. The first-moment maps, pixel-to-pixel line modeling, assuming local thermodynamic equilibrium (LTE), and position-velocity diagrams of the CH3CN J=13–12 K-line emission all show a velocity gradient along the major axis of the source, coupled with an increase in velocity at small radii, consistent with Keplerian-like rotation. The LTE line modeling shows that where CH3CN J=13–12 is excited, the temperatures in the disk range from 70 to at least 300K and that the H2 column density peaks at 2.8×1024 cm−2. In addition, we present Atacama Pathfinder Experiment (APEX) 12CO observations which show a large-scale outflow from AFGL 4176 perpen- dicular to the major axis of mm1, supporting the disk interpretation. Finally, we present a radiative transfer model of a Keplerian disk surrounding an O7 star, with a disk mass and radius of 12M⊙ and 2000AU, that reproduces the line and continuum data, further supporting our conclusion that our observations have uncovered a Keplerian disk around an O-type star.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2015, American Astronomical Society. This is an author produced version of a paper published in Astrophysical Journal Letters. Uploaded in accordance with the publisher's self-archiving policy |
Keywords: | radiative transfer; techniques: interferometric; circumstellar matter; stars: formation; stars: massive; ISM: jets and outflows |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Oct 2015 15:59 |
Last Modified: | 18 Jan 2018 13:07 |
Published Version: | http://dx.doi.org/10.1088/2041-8205/813/1/L19 |
Status: | Published |
Publisher: | American Astronomical Society |
Identification Number: | 10.1088/2041-8205/813/1/L19 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:91177 |