The Blue Straggler RS Canum Venaticorum Star S1082 in M67: A Detailed Light Curve and the Possibility of a Triple* **

摘要: Using both photometric and spectroscopic data, we present a picture of the very unusual blue straggler S1082 in old open cluster M67 whose light is sum close binary (P = 1.0677978 days) another member. The primary third star are stragglers their own rights. relative photometry with millimagnitude accuracy, provide complete V-band curve for system show number features: brightness variations at 0.01?0.03 mag level from month to all phases, narrow broad secondary eclipse, differences between phases 0.25 0.75, short duration (~1 hr) drops brightness. Much light-curve variation appears be because spot activity on cooler, fainter, nearly synchronized component binary. We use spectra several sources constrain temperatures three known components, flux contributions, rotational velocities, radial velocities. data clearly that brightest (narrow-line component) seen spectrum an orbit period P 1189 ? 7 days eccentricity e 0.57 0.08, although cannot prove there dynamical link it systematic velocities stars indicate they members cluster. Our models cooler lies main sequence near turnoff, while hotter extension blueward thus qualifies as by itself. reduction masses compared previous indicates possible more massive formed merger just two turnoff-mass stars.