In contrast to the formation of low-mass stars, it is not clear whether these objects form via disk accretion or by coalescence processes. In addition, these objects are often associated with very strong energetic outflows and winds and finally explode as supernovae, thereby strongly modifying the physical conditions in their environment.

The massive stars (M > 8Msun) form so quickly that they are embedded inside dense molecular cloud cores for a considerable fraction of their lifetime and many of them are thus hard to observe by astronomers during their childhood. Because these stars are also very hot, they have a rather big impact on the dense cloud around them:  The dust gets molten and/or blown away, the gas becomes ionized. Sometimes they even start destroying accretion disks around neighbouring (lower-mass) stars.  Once these massive stars are hot enough they create "Ultracompact HII Regions" (UCHIIs). In extragalactic systems, the only sign of star formation we can trace is the formation of such massive stars.

At MPIA we are presently hunting for the massive and cold protostars, search for disks, and determine the initial mass function in regions of massive star formation.