This paper discusses two new observational results for the molecular gas associated with ultracompact (UC) HII regions. The first is the recent discovery by Henkel et al. (1995) that the 32S/34S abundance ratio, as inferred from observations of CS isotopes, is strongly correlated with galactocentric distance while 34S/33S is not. The second is a statistical study of high velocity CO (J=1-0) toward a sample of 94 UCHII regions. Fully 90% of this sample has excess line wing emission with velocities >15 km/s. Several of these have been mapped and found to be bipolar flows. The mass, kinetic energy, and rate of momentum transport in the flows are about an order of magnitude greater than found toward low mass stars. It is postulated that the flows are driven by massive stars, although not necessarily the ionizing stars of the observed UCHII regions.
Revista Mexicana de Astronomia y Astrofisica Conference Series
- Pub Date:
- December 1995