ALLS KNOT QUIET ON THE RECOMBINATION FRONT

Molecular clouds are clumpy on length scales down to the limits of obs ervational resolution. At least some ultracompact HII regions (UCHIIR) may result from the interaction of a young early type star and this t ype of cloud. The clumps can act as reservoirs of ionized gas distribu ted within the HII region. These models reproduce the relatively long Lifetimes implied by the population statistics of UCHIIR. We present l ine profile and emission measure plots based on the simplest case wher e the flow remains supersonic through to a recombination front. The mo rphology agrees with the shell-like UCHIIR as classified by Churchwell . The predicted line profiles are broad and double peaked with a separ ation of about 50 km s(-1) for the example given.