EPoS Contribution
EPoS Contribution
Infrared Spectroscopy of massive protostellar objects and their environment

Jan Pitann
Max-Planck-Institut für Astronomie, Heidelberg, Germany
Several cold and massive dust clumps were identified by the 170micron ISO Serendipity Survey (ISOSS) and later observed in the submillimeter and millimeter regime. Candidates for massive protostars were found in this regions. Infrared dark clouds can harbour young protostellar objects which can evolve into massive stars later. We present a set of infrared spectra observed for this objects by Spitzer/IRS. The objects in our sample representing different evolutionary stages. Two opposed case will be shown in detail. ISOSS J18364−0221 West is a young protostar deeply embedded in the surrounding dust clump with indications for collaps and outflows. The spectrum reveals a variaty of ice and dust features. The ISOSS J20153+3453 region represents a more evolved stage revealing a PDR-like sturcture of warm gas and polycylcic aromatic hydrocarbons. Different diagnostical approaches were used. For example, we determine the extinction from the silicate absorptions along the line of sight. By classifing the PAH features we could draw conclusions about the UV radiation field. We studied the spatial distribution of several spectral lines. This results were correlated with previous observations to develop a consistent picture about the regions and the protostellar objects within.
Collaborators:
M. Hennemann, CEA, France
O. Krause, MPIA, Germany
S. Birkmann, ESTEC, Netherlands
J. Bouwman, MPIA, Germany
Th. Henning, MPIA, Germany
Suggested Session: Massive Stars