Three-Color Photometry of YZ BOÖTIS.

Abstract

A total of 216 photoelectric observations on the UBV system have been obtained for YZ , an RR Lyrae star with a period of about hours. The ascending branches of the light-curves and the amplitudes are relatively repetitive, but the descending branch may be subject to small changes from cycle to cycle. The position of the YZ loop in the U - B, B - V diagram suggests that the variable is probably not reddened. A revised ephemeris for the times of maximum brightness has been obtained: Max. = HJD 2438206.6961 + 0.104091485 E.