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EP: Extraterrestrische Physik
EP 13: Astrophysik: Interstellares Medium und Sternentstehung
EP 13.2: Fachvortrag
Wednesday, March 15, 2006, 15:00–15:15, B
The rapid and hidden formation of massive stars — •Jürgen Steinacker1,2, Rolf Chini3, Markus Nielbock3, Vera Hoffmeister3, and Dieter Nürnberger4 — 1Max-Planck-Institut für Astronomie, Königsstuhl 17, D-69117 Heidelberg, Germany — 2Astronomisches Rechen-Institut, Mönchhofstr. 12-14, D-69120 Heidelberg, Germany — 3Astronomisches Institut, Ruhr-Universität Bochum. D-44780 Bochum, Germany — 4European Southern Observatory, Casilla 19001, Santiago 19, Chile
While many observational results support that low-mass stars form via an accretion disk, the formation of massive stars remains to be a mystery. They form on short time scales of some 104 years, remain invisible at most wavelengths until they reach the main sequence, and are low in number compared to stars of smaller mass. The two major scenarios of formation by stellar merger or by an accretion disk are briefly reviewed. We report on the detection of the largest circumstellar disk known sofar being located in the massive star formation region M17. Making use of the rare configuration that the disk is seen in silhouette against the background radiation at λ=2.2 µm, we present results of a detailed structure model applied to the high-resolution NAOS/CONICA image. The mass of the massive disk candidate is discussed depending on the assumed distance and the dust model and ranges between 0.06 and 14.6 Msun. Due to the unknown structure of the innermost part of the edge-on circumstellar disk, the observational data are not sufficient to constrain the stellar mass yet. For the stellar and disk mass being equal, we find the disk to be stable against gravitational instabilities.