Searching for the cycle period in chromospherically active stars

The detection and analysis of line emission of the CaII, H(396.8nm) and K(393.3nm) have confirmed the chromospheric activity of some single and binaries stars. This activity is associated to the presence of magnetic fields which in turn are produced by internal convective flows along with stellar rotation producing a long-term photometric cycle length related to the apparition and vanishing of superficial stellar spots. We present a photometric study of stars of the type RS CVn, Rotationally variable Star and BY Dra, that have shown evidence of chromospheric activity. The analysis of these measurements has allowed us to delimit periods of rotation. In addition, we have detected and measured the cycle length in some cases. It allows us to complement previous investigations and in some cases to determine for the first time the presence of a long photometric cycle, contributing to complement the link between rotation and magnetic cycles.