Selection

Current status of observations

The source selection is based on various factors, basically star formation activity, morphology, dynamic driving mechanisms, and evolutionary stage . The full sample allows us to systematically study the effects of parameters like cluster size, stellar wind activity, FUV photon leakage from compact HII regions, evolutionary stage (the expansion time may evolve along the sequence Orion, M17, NGC 7538, diamond ring in Cyg X), sculpting of pillars, spires, & bright rim clouds (M16, NGC 7538), driving mechanism (thermal expansion, stellar wind, radiation pressure: RCW 120, RCW 49, RCW 79), environmental effects (isolated O stars such as RCW 120 vs. clusters), converging flows and impact of nearby OB association (Cyg X), mini starburst activity (NGC 6334), starburst activity fueled by the converging flows where spiral arm meets the central bar (W43), compact versus dispersed star formation (RCW 49, NGC 6334) and small versus large scale filamentary structure (W40, RCW36, NGC 6334, Cyg X).

While one goal of this program is to understand the individual factors involved in the feedback of massive stars on their environment, we specifically include three large, complex regions (NGC 6334, W43, Cyg X) as the concerted action of multiple, nearly simultaneous regions of massive star formation in close proximity will be key to understanding observations of massive star forming complexes in external galaxies.

Source Information