Clumpy ultracompact H II regions I : Fully supersonic wind - blown models

We propose that a significant fraction of the ultracompact H II regions found in massive star-forming clouds are the result of the interaction of the wind and ionizing radiation from a young massive star with the clumpy molecular cloud gas in its neighbourhood. Distributed mass loading in the flow allows the compact nebulae to be long-lived. In this paper, we discuss a particularly simple case, in which the flow in the H II region is everywhere supersonic. The line profiles predicted for this model are highly characteristic , for the case of uniform mass loading. We discuss briefly other observational diagnostics of these models.