The blue straggler S 1082: A triple system in the old open cluster M 67

We present a photometric and spectroscopic study of the blue straggler S 1082 in the open cluster M 67. 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.