FALLSCHEER C., BEUTHER H., SAUTER J., WOLF S. and ZHANG Q.
Abstract (from CDS):
Many questions remain regarding the properties of disks around massive prototstars. Here, we present the observations of a high-mass protostellar object including an elongated dust continuum structure perpendicular to the outflow. Submillimeter Array 230 GHz line and continuum observations of the high-mass protostellar object IRAS 18151-1208 along with single-dish IRAM 30 m observations afford us high spatial resolution (0".8) as well as recovery of the extended emission that gets filtered out by the interferometer. The observations of 12CO confirm the outflow direction to be in the southeast-northwest direction, and the 1.3 mm continuum exhibits an elongation in the direction perpendicular to the outflow. We model the physical parameters of the elongated structure by simultaneously fitting the observed spectral energy distribution and the brightness profile along the major axis using the 3D Radiative Transfer code MC3D. Assuming a density profile similar to that of a low-mass disk, we can also reproduce the observations of this high-mass protostellar object. This is achieved by using the same density distribution and flaring parameters as were used in the low-mass case, and scaling up the size parameters that successfully modeled the circumstellar disk of several T Tauri stars. We also calculate that a region within the inner 30 AU of such a high-mass disk is stable under the Toomre criterion. While we do not rule out other scenarios, we show here that the observations in the high-mass regime are consistent with a scaled-up version of a low-mass disk. Implications on high-mass star formation are discussed.