The nature of the variable Galactic center source GCIRS 16SW revisited: A massive eclipsing binary

We present a reanalysis of our H- and K-band photometry and light curves for GCIRS 16SW, a regular periodic source near the Galactic center. These data include those presented by DePoy et al.; we correct a sign error in their reduction, finding GCIRS 16SW to be an eclipsing binary with no color variations. We find the system to be an equal-mass overcontact binary ( both stars overfilling their Roche lobes) in a circular orbit with a period P = 19.4513 days and an inclination angle i = 71 degrees. This confirms and strengthens the findings of Martins et al. that GCIRS 16SW is an eclipsing binary composed of two similar to 50 M-. stars, further supporting evidence of recent star formation very close to the Galactic center. Finally, the calculated luminosity of each component is close to the Eddington luminosity, implying that the temperature of 24,400 K given by Najarro et al. might be overestimated for these evolved stars.