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Models and observations of the millimeter and submillimeter molecular line emission of bright -rimmed clouds

Christopher Hugh De Vries, University of Massachusetts Amherst


We present the results of a comparison of new millimeter and submillimeter molecular line survey of bright-rimmed clouds, observed at FCRAO in the CO (J = 1 → 0), C18O (J = 1 → 0), HCO+ (J = 1 → 0), H 13CO+ (J = 1 → 0), and N 2H+ (J = 1 → 0) transitions, at the HHT in the CO (J = 2 → 1), HCO+ ( J = 3 → 2), HCO+ (J = 4 → 3), H13CO+ (J = 3 → 2), and H13CO+ (J = 4 → 3), and at the CSO in the HCO+ (J = 4 → 3) and H13CO+ (J = 4 → 3) molecular line transitions with synthetic observations of a hydrodynamic shock driven triggered star formation model. We also present observations of three Bok globules done for comparison with the bright-rimmed clouds. We find that the appearance of the millimeter CO and HCO+ emission is dominated by the morphology of the shock front in the bright-rimmed clouds. The HCO + (J = 1 → 0) emission tends to trace the swept up gas ridge and overdense regions which may be triggered to collapse as a result of sequential star formation. The morphologies of the observed bright-rimmed cloud are in good agreement with the our modeled emission. Five of the seven bright-rimmed clouds we observe seem to have an outflow, however only one shows the spectral line blue-asymmetric signature that is indicative of infall, in the optically thick HCO+ emission. We also present evidence that in bright-rimmed clouds the nearby shock front may heat the core from outside-in thereby washing out the normally observed line infall signatures seen in isolated star forming regions. We find that the derived core masses of these bright-rimmed clouds are similar to other low and intermediate mass star forming regions.

Subject Area


Recommended Citation

De Vries, Christopher Hugh, "Models and observations of the millimeter and submillimeter molecular line emission of bright -rimmed clouds" (2003). Doctoral Dissertations Available from Proquest. AAI3078676.