Hα, Ca IRT, and Ca H&K excess equivalent width versus time. The thin black lines are the maximum power sine waves derived from our periodogram analysis and thin gray lines represent extrapolations to emphasize phase jumps. Vertical dashed lines denote the different subsamples. If the rotation period of the best-fit solution deviates significantly from the literature value of 12 days, we do not plot it. In case of Ca H&K, we removed two outliers.