The VLTI and the Galactic Center He I Cluster

Abstract

The infrared spectra of early-type stars are powerful diagnostic tools for studying the process of mass-loss via a stellar wind and for determining fundamental stellar parameters. First quantitative infrared spectroscopic studies of the brightest members of the cluster of HeI objects in the center of our Galaxy have not only confirmed the stellar nature of these objects, but have also yielded stellar parameters. These indicate that the He I emission line stars are evolved blue supergiants close to the evolutionary stage of Wolf-Rayet stars. The HeI objects belong to a a stellar cluster of massive stars formed some 5 million years ago. Our results suggest that this stellar cluster may dominate the energetics and radiation field of the central parsec of the Galaxy. It is, therefore crucial to perform quantitative infrared spectroscopy of the other, fainter early-type stars of the cluster to better understand their role in powering the central parsec. To achieve this task we need to obtain not only moderate high S/N spectra of the fainter stars but also accurate continuum measurements for each object. Because of the enormous crowding present in the Galactic Center, the VLTI presents a unique opportunity to perform these flux measurements.KeywordsStellar WindGalactic CenterStar ClusterDiffuse EmissionStellar ClusterThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.