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

TL;DR

This study confirms that Cyg OB2-B17 is a massive, evolved eclipsing binary system with two supergiant stars, providing key data for understanding massive star evolution and related energetic phenomena.

Contribution

It presents the first detailed photometric and spectroscopic analysis of Cyg OB2-B17, establishing its binary nature and preliminary stellar classifications.

Findings

Period of 4.0217 days with precise measurement

Components classified as O7 and O9 supergiants

Consistent radial velocity and light curve data

Abstract

Massive, eclipsing, double-lined, spectroscopic binaries are not common but are necessary to understand the evolution of massive stars as they are the only direct way to determine stellar masses. They are also the progenitors of energetic phenomena such as X-ray binaries and gamma-ray bursts. We present a photometric and spectroscopic analysis of the candidate binary system Cyg OB2-B17 to show that it is indeed a massive evolved binary. We utilise V band and white-light photometry to obtain a light curve and period of the system, and spectra at different resolutions to calculate preliminary orbital parameters and spectral classes for the components. Our results suggest that B17 is an eclipsing, double-lined, spectroscopic binary with a period of 4.0217+/-0.0004 days, with two massive evolved components with preliminary classifications of O7 and O9 supergiants. The radial velocity and light curves are consistent with a massive binary containing components with similar luminosities, and in turn with the preliminary spectral types and age of the association.