Molecular line CN , CS and mm continuum observations of two intermediate- to high-mass star-forming regions – IRAS 20293+3952 and IRAS 19410+2336 – obtained with the Plateau de Bure Interferometer at high spatial resolution reveal interesting characteristics of the gas and dust emission .
In spite of the expectation that the CN and CS morphology might closely follow the dense gas traced by the dust continuum , both molecules avoid the most central cores .
Comparing the relative line strengths of various CN hyperfine components , this appears not to be an opacity effect but to be due to chemical and physical effects .
The CN data also indicate enhanced emission toward the different molecular outflows in the region .
Regarding CS , avoiding the central cores can be due to high optical depth , but the data also show that the CS emission is nearly always associated with the outflows of the region .
Therefore , neither CS nor CN appear well suited for dense gas and disk studies in these two sources , and we recommend the use of different molecules for future massive disk studies .
An analysis of the 1 and 3 mm continuum fluxes toward IRAS 20293+3952 reveals that the dust opacity index \beta is lower than the canonical value of 2 .
Tentatively , we identify a decreasing gradient of \beta from the edge of the core to the core center .
This could be due to increasing optical depth toward the core center and/or grain growth within the densest cores and potential central disks .
We detect 3 mm continuum emission toward the collimated outflow emanating from IRAS 20293+3952 .
The spectral index of \alpha \sim 0.8 in this region is consistent with standard models for collimated ionized winds .