A hot compact dust disk around a massive young stellar object
Nature Publishing Group
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which strong radiation pressure might halt mass infall. Massive stars may form by stellar merging, although more recent theoretical investigations suggest that the radiative-pressure limit may be overcome by considering more complex, non-spherical infall geometries. Clear observational evidence, such as the detection of compact dusty disks around massive young stellar objects, is needed to identify unambiguously the formation mode of the most massive stars. Here we report near-infrared interferometric observations that spatially resolve the astronomical-unit-scale distribution of hot material around a high-mass ( approximately 20 solar masses) young stellar object. The image shows an elongated structure with a size of approximately 13 x 19 astronomical units, consistent with a disk seen at an inclination angle of approximately 45 degrees . Using geometric and detailed physical models, we found a radial temperature gradient in the disk, with a dust-free region less than 9.5 astronomical units from the star, qualitatively and quantitatively similar to the disks observed in low-mass star formation. Perpendicular to the disk plane we observed a molecular outflow and two bow shocks, indicating that a bipolar outflow emanates from the inner regions of the system.
This work was done in part under contract with the California Institute of Technology (Caltech), funded by NASA through the Sagan Fellowship Program (S.K. is a Sagan Fellow). We thank the ESO Paranal staff for support and their efforts in improving the VLTI. This paper is based on observations made with ESO telescopes at the La Silla Paranal Observatory and archival data obtained with the Spitzer Space Telescope, operated by the Jet Propulsion Laboratory, Caltech, under a contract with NASA. We also used data acquired with APEX, a collaboration between the Max-Planck-Institut für Radioastronomie, ESO, and the Onsala Space Observatory.
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.
Vol. 466, pp. 339 - 342
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