GCIRS 16SW: A massive eclipsing binary in the Galactic center

We report on the spectroscopic monitoring of GCIRS 16SW, an Ofpe/WN9 star and LBV candidate in the central parsec of the Galaxy. SINFONI observations show strong daily spectroscopic changes in the K band. Radial velocities are derived from the He I 2.112 mu m line complex and vary regularly with a period of 19.45 days, indicating that the star is most likely an eclipsing binary. Under various assumptions, we are able to derive a mass of similar to 50 M circle dot for each component.