CHROMOSPHERICALLY ACTIVE STARS .12. ADS 11060-C - A DOUBLE-LINED K-DWARF BINARY IN A QUINTUPLE SYSTEM

ADS 11060 C is a double lined spectroscopic binary with a period of 25 .7631 days and an eccentricity of 0.565. Spectral types of two stars a re estimated as K7 V M0 V with a magnitude difference of about 0.55 ma g in V. The stars appear to be somewhat metal rich with respect to the Sun. Despite the relatively large masses of 0.53 and 0.51 M., our pho tometric observations find no evidence for eclipses and we estimate an inclination of 77-degrees +/- 11-degrees. ADS 11060 C is, however, ph otometrically variable with a period of 9 +/- 1 day and an amplitude o f 0.05 mag in V. Thus, it is a newly identified BY Draconis variable. The center-of-mass velocity of ADS 11060 C and an estimated parallax o f 0.030'' support its physical association with ADS 11060 AB, making t his a quintuple system. The projected separation of the AB-C system is nearly 1200 AU. Although the log lithium abundances of the two compon ents of ADS 11060 C are only upper limits, less-than-or-equal-to 0.14, lithium abundances of the AB-C components appear to be consistent wit h those of similar stars in the alpha Persei and Pleiades clusters, su ggesting an age of about 70 Myr for ADS 11060 AB-C. The system is a po ssible member of the Pleiades moving group. Listed as an optical count erpart to a source in the ROSAT Wide Field Camera extreme-ultraviolet bright source catalog, both ADS 11060 AB and C may contribute to the o bserved flux.