Abstract:

The eclipsing binary system DV Psc has been known to be magnetically active for almost two decades. However, there has been no evidence of a magnetic cycle on this system until recently. This study focuses on the long-term photometric monitoring of DV Psc between 2005-2017. A total of 50 individual light curves in BVRI optical bands were collected, in order to investigate its magnetic activity and cycle, as well as determine its orbital and physical properties. The combined photometric and spectroscopic observations of this study resulted in a unified model for the system, which describes accurately the light curves throughout the years, as a result of the variable spot activity. A total of 105 new times of minimum light are calculated through the entire time span of observations and they are combined with the 203 bibliographic ones since 1997, increasing significantly the existing sample. This resulted in an accurate ephemeris and an updated O-C diagram for a total span of 20 yr (1997-2017). It is found that the system exhibits intense magnetic activity, which is shown through the strong asymmetries on the light curves (O'Connell effect) and the periodic variation of the O-C diagram. The existence of a third body, orbiting the eclipsing binary with a period of P_orb=9.79±0.60 yr in an eccentric orbit with eccentricity e=0.83±0.24, as well as a magnetic cycle of 14.74±0.84 yr are most likely connected with this variability. The absolute physical parameters of the system are calculated for a new and unified model, which explains the light curves through the entire observing season. The evolution state of DV Psc is studied through the mass-radius and temperature-luminosity (HR) diagrams, as well as the location of the two components with respect to the ZAMS and TAMS region.

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