Millimeter and Submillimeter Wavelength Continuum Observations of Massive Young Stellar Objects

Abstract

The continuum emission from nine sources listed in the IRAS Point Source Catalog, and believed to be massive young stellar objects, has been mapped at wavelengths 1100 and 800 μm, and five of the nine have been mapped at 450 μm. For each source, the new data have been combined with the published IRAS flux densities, and the source spectra have been fitted by two blackbody curves. The long wavelength data have been used to characterize the cool dust via its emissivity index, optical depth (at 450 μm), and temperature. A separate curve was fitted to the IRAS data points at the two shortest wavelengths to characterize the hot dust. The fits are best with 450 m optical depths less than 0.1 in all cases. The derived dust temperatures range from 28 to 41 K for the cool component, and from 100 to 144 K for the hot component. The dust temperatures of the cool components are equal to, or greater than, the gas temperatures within the uncertainties. The dust masses are typically a few solar masses. The average of the gas-to-dust ratios for seven sources is 45±10.