Program: GS-2007A-C-5

We are undertaking a major survey of the young massive star population of the Milky Way. One aspect of this work is the relationship between hot molecular cores (HMCs) and massive young stellar objects (MYSOs) or compact HII regions. A potential tracer of the evolutionary state is the CO 4.65um fundamental line, which should arise in the interface between star and natal molecular cloud. In principle such observations can allow us to detect infall/outflow signatures as a function of evolutionary status. Since Phoenix will not be offered after March 2007 we are requesting time to observe the feasbile targets in the outer Galactic Plane, where our survey is now complete. We will use these velocity resolved observations of the fundamental CO bandhead around 4.67um to help create new models for the interaction between the ionised wind from the young star and the natal molecular cloud.