The eclipsing, double-lined, Of supergiant binary Cygnus OB2-B17

摘要

Context. Massive, eclipsing, double-lined, spectroscopicbinaries are not common but are necessary to understand the evolutionof massive stars as they are the only direct way to determine stellarmasses. They are also the progenitors of energetic phenomena such asX-ray binaries and -ray bursts. Aims. We present a photometric and spectroscopic analysis of thecandidate binary system Cyg OB2-B17 to show that it is indeed a massiveevolved binary. Methods. We utilise V band and white-light photometry toobtain a light curve and period of the system, and spectra at differentresolutions to calculate preliminary orbital parameters and spectralclasses for the components. Results. Our results suggest that B17 is an eclipsing, double-lined, spectroscopic binary with a period of days, with two massive evolved components with preliminaryclassifications of O7 and O9 supergiants. The radial velocity and lightcurves are consistent with a massive binary containing components withsimilar luminosities, and in turn with the preliminary spectral typesand age of the association. Key words: binaries: eclipsing - binaries: spectroscopic - stars: early-type - stars: fundamental parameters - stars: evolution - stars: individual: Cyg OB2 B17