The New RS CVn Binary V1034 Her Revisited and the orbital period - Activity relation of Short-period RS CVn binaries using photometric distortion amplitude

TL;DR

This study presents new photometric observations and spot modeling of the RS CVn binary V1034 Her, revealing long-term light curve changes, active longitude belts, and a correlation between activity and orbital period.

Contribution

It introduces detailed spot modeling with one- and two-spot solutions and establishes a link between photometric distortion amplitude and orbital period in short-period RS CVn binaries.

Findings

Two-spot model better reproduces light-curve distortions.

Active longitude belts may switch over time.

Activity increases as orbital period decreases.

Abstract

This paper presents new CCD BVRI light curves of the newly discovered RS CVn eclipsing binary V1034 Her in 2009 and 2010, which shapes are different from the previous published results. They show asymmetric outside eclipse and we try to use a spot model to explain the phenomena. Using the Wilson-Devinney program with one-spot or two-spots model, photometric solutions of the system and starspot parameters were derived. Comparing the two results, it shows that the case of two spots is better successful in reproducing the light-curve distortions. For all the spot longitudes, it suggests that the trend towards active longitude belts and each active longitude belts might be switch. Comparing the light curves of 2009 and 2010, it indicates that the light curve changes on a long time scale of one year, especially in phase 0.25. In addition, we also collected the values of the maximum amplitudes of photometric distortion of the short-period RS CVn binary. We found for the first time that there is a trend of increasing activity with decreasing the orbital period. Finally, fitting all available light minimum times including our newly obtained ones with polynomial function confirmed that the orbital period of V1034 underwent up increase.