EPoS Contribution
EPoS Contribution
The interplay between molecular and ionized gas surrounding the massive embedded star AFGL 2591

Katharine Johnston
MPIA, Heidelberg, Germany
In order to investigate whether feedback processes such as photo- and shock ionization have an important effect on the geometry of the circumstellar dust and gas around forming massive stars, we have modelled the near-IR to sub-millimetre SEDs and IR images of the embedded massive star AFGL2591, using the standard envelope and disc geometry commonly applied to low-mass protostars. In combination with our Monte Carlo radiation transfer dust code, we have used a genetic search algorithm to explore parameter space and find the best fitting model, allowing us to get a handle on the source geometry and its physical properties, as well as their uncertainties, showing it is a powerful method to explore and understand the large parameter space encountered while fitting SEDs of massive embedded stars. In addition, we have new high sensitivity VLA 3.6cm observations of AFGL2591 that uncover a collimated jet towards VLA3, the source coincident with the central illuminating object of AFGL 2591 at infrared wavelengths. We also present C18O(1-0) CARMA observations which trace the densest parts of the outflow from AFGL 2591, as well as a flattened structure perpendicular to the outflow direction at the rest velocity of the cloud. The blue-shifted C18O(1-0) emission shows a Hubble law relationship, with the dense gas increasing in velocity away from the source, as well as higher collimation at higher velocities, hence showing many similarities to the properties of outflows around low-mass protostars.
Shepherd, D. S., NRAO, USA
Robitaille, T. P., MPIA, Germany
Wood, K., Univ. of St Andrews, UK
Beuther, H., MPIA, Germany