The blue straggler S1082: a triple system in the old open cluster M67

Abstract

We present a photometric and spectroscopic study of the blue straggler S1082 in the open cluster M67. Our observations confirm the previously reported 1.07 day eclipse light curve and the absence of large radial-velocity variations of the narrow-lined star. However, we find two more spectral components which do vary on the 1.07 day period. We conclude that the system is triple. We fit the light and radial-velocity curves and find that the total mass of the inner binary is more than twice the turnoff mass and that the outer companion to the binary is a blue straggler on its own account. We briefly discuss formation scenarios for this multiple system.