On the nature of the fast moving star S2 in the Galactic Center

Abstract

We analyze the properties of the star S2 orbiting the supermassive black hole at the center of the Galaxy. A high quality SINFONI H and K band spectrum obtained from coadding 23.5 hours of observation between 2004 and 2007 reveals that S2 is an early B dwarf (B0-2.5V). Using model atmospheres, we constrain its stellar and wind properties. We show that S2 is a genuine massive star, and not the core of a stripped giant star as sometimes speculated to resolve the problem of star formation so close to the supermassive black hole. We give an upper limit on its mass loss rate, and show that it is He enriched, possibly because of the presence of a magnetic field.

4 pages, 5 figures, ApJ letters accepted

References in corpus (6)

• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• The structure of the nuclear stellar cluster of the Milky Way
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• The VLT-FLAMES Survey of Massive Stars: Stellar parameters and rotational velocities in NGC3293, NGC4755 and NGC6611
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