PROPERTIES OF THE MOLECULAR CLUMP AND THE ASSOCIATED ULTRACOMPACT H II REGION IN THE GAS SHELL OF THE EXPANDING H II REGION SH 2-104

Abstract

We study the physical and chemical properties of the molecular clump hosting a young stellar cluster, IRAS 20160+3636, which is believed to have formed via the “collect and collapse” process. Physical parameters of the UC Hii region associated with the embedded cluster are measured from the radio continuum observations. This source is found to be a typical Galactic UC Hii region, with a B0.5 type exciting star, if it is ionized by a single star. We derive a CN/HCN abundance ratio larger than 1 over this region, which may suggest that this clump is being affected by the UV radiation from the Hii region.