The Initial Conditions of High Mass Star-Formation

Abstract

Studies in the field of star formation have led to a good understanding of low mass star-formation. However there are both theoretical and observational challenges that hinder a similar understanding of high mass star-formation. Studies on the initial stages of high mass star formation would be the best strategical advance for observers. Only recently have clouds with the potential of forming high-mass stars and /or clusters, but still yet largely devoid of stellar objects, been identified: Infrared Dark Clouds.<br /> As part of my PhD thesis, I conducted a comprehensive observational study of infrared dark clouds (IRDCs). IRDCs are cold, dense molecular clouds seen in silhouette against the bright diffuse mid-infrared (MIR) emission of the Galactic plane. The main objective was to identify the physical and chemical properties of the massive cores embedded in IRDCs, the progenitors of high-mass stars. Observations were made with mm/cm single dish telescopes, <br /> interferometers and mid-infrared data from Space Telescopes (MSX/SPITZER) for the study.<br /> I find that IRDCs harbour precluster cores which are gravitationally bound and turbulent. These cores show a high degree of deuteriation and depletion. In some cases cores harbour clusters at a very early evolutionary stage showing that massive stars can form within IRDCs. This work has provided evidence that within IRDCs, the long sought progenitors of high mass stars can be found.