Evidence for disks around young high-mass stars
Astronomical Institute, Ruhr-Universität Bochum, Germany, and Facultad de Ciencias, Universidad Católica del Norte, Antofagasta, Chile
Astronomical Institute, Ruhr-Universität Bochum, Germany
European Southern Observatory, Santiago, Chile
Abstract
The formation of high-mass stars remains a poorly understood process despite growing observational evidence in favour of accretion from a circumstellar disk onto a protostellar core. The high fraction of multiple stellar systems among the most massive stars and the fact that these stars are usually born in dense clusters can alternatively be explained by merging of intermediate-mass stars. Here we review some observations that provide direct evidence for large (~ 10,000 − 20,000 AU) disks and/or dusty envelopes seen in emission and absorption around high-mass stars. The objects are all members of the young cluster in M 17 and have been investigated by multicolor photometry and spectroscopy.