Testing the Evolutionary Sequence of High Mass Protostars with Carma

We present 1 resolution CARMA observations of the 3mm continuum and 95GHz CH3OH masers toward 14 candidate high mass protostellar objects (HMPOs). Dust continuum emission is detected toward seven HMPOs, and CH3OH masers toward 5 sources. The 3mm continuum sources have diameters < 2× 10AU, masses between 21 and 1200M⊙, and volume densities > 10 8 cm. Most of the 3mm continuum sources are spatially coincident with compact H II regions and/or water masers, and are presumed to be formation sites of massive stars. A strong correlation exists between the presence of 3mm continuum emission, 22GHz H2O masers, and 95GHz CH3OH masers. However, no 3mm continuum emission is detected toward ultracompact H II regions lacking maser emission. These results are consistent with the hypothesis that 22GHz H2O masers and CH3OH masers are signposts of an early phase in the evolution of an HMPO before an expanding H II region destroys the accretion disk. Subject headings: stars: formation – masers