Observations of the young stellar association ON2

Results are presented from a study of the star-formation region ON2 in molecular lines and the far-infrared. Ammonia maps of the dense gas show a double structure, with young stars located around the cloud edges. Localized heating of the molecular gas is evident near these early-type stars, and molecular hydrogen densities of $$\approx 10^5\enspace \text {cm}^{-3}$$ are required to maintain the observed gas temperature through gas/dust coupling.