NEW PHOTOMETRIC STUDY OF THE INTERACTING BINARY STAR SYSTEM Y PISCIUM

Abstract

We present a new photometric study of Y Piscium (Y Psc), which includes BVI light curves and a period analysis. With an orbital period of 3.77 days, this neglected system undergoes period changes described by an overall quadratic ephemeris with oscillating variability superimposed. Variations in the light curve and ephemeris curve, possibly resulting from changes in the accretion structure and mass transfer rate, suggest that Y Psc may be a direct-impact system like U Coronae Borealis and U Sagittae, which are known to exhibit variable accretion states. The 0.46 m modified Cassegrain telescope at the Kutztown University Observatory (Kutztown, PA) was used to obtain the new CCD photometry over 18 nights of observation between 2011 October 5 and 2012 January 15. We present a new photometric model that was determined using the computer program PHOEBE and suggest a reclassification of the spectral type of the primary star. An analysis of previously recorded times of minimum, in conjunction with our observations, was used to suggest possible physical mechanisms intrinsic to the system. These include magnetic activity (Applegate mechanism) and angular momentum transfer, while the possibility of a third body is ruled out. The results presented here demonstrate that Y Psc is an excellent candidate for a high-resolution spectroscopic study.