Photometric Study of Two Recently Discovered Variable Stars in the Field of BS Cas

Natalia A. Virnina, Radek Kocian, Lubomir Hambalek, Pavol Dubovsky, Ivan L. Andronov, Igor Kudzej

Published 2012-02-09, updated 2012-07-15Version 3

Two recently discovered variable stars (CzeV134 = GSC 3682 0018 = USNO-A2.0 1425-1870026 and CzeV135 = GSC 3682 2051 = USNO-A2.0 1425-1825909 = V1094 Cas), which have been identified in the field of the W UMa variable star BS Cas, are studied in the present paper. The phase curves and finding charts for these stars are presented. The ephemeris and other photometric parameters were computed. The phenomenological features indicate that the first star (CzeV134) is probably a low-amplitude RRc Lyrae - type variable star with the period P = 0.419794\pm0.000029 d and the initial epoch T0 = HJD2453236.50412\pm0.00056. The amplitude and the shape of the light curve are variable possibly indicating the Blazhko phenomenon. The second star (CzeV135) was classified as an EW-type binary system of subtype A. However, a {\beta} Lyrae type may not be excluded, as various classification parameters lie in a range of overlapping values for both classes. The period P=0.51429090\pm0.00000012 d and the initial epoch T0 = HJD2454543.7920\pm0.0006. The O'Connell effect is clearly visible. There are slight changes of this effect, noticeable while comparing different seasons of observations. O-C diagrams for these stars were analyzed.