Carbon Monoxide Emission from Stars in the IRAS and Revised AFGL Catalogs. I. Mass Loss Driven by Radiation Pressure on Dust Grains

We surveyed infrared bright stars in the IRAS and Revised AFGL catalogs in the J = 2 → 1 rotational transition of carbon monoxide. Broad lines were detected in 39 objects not previously see in CO emission, including the unusual supergiant VY CMa, the bright giant star W Hya, and some stars first discovered in the IRAS survey about which very little is known. A plot of momentum in the outflowing wind, MV, deduced from a simple model for the CO emission versus momentum in the stellar radiation field, L_*/c, reveals eleven objects for which MV appears to be larger than L_*/c. These objects, nine of which are carbon-rich, are distinguished by either an early-type central star or a large outflow velocity V, or both.