Rotational period from auto-correlation of the CoRoT-14 photometry. This diagram is created by correlating the light curve with a temporally-shifted version of itself (the lag listed on the X-axis). The broad local maxima at multiples of 5.66 days (marked by the vertical black lines) correspond to the rotation of the star, visible through the photometric footprints of activity-induced variations on the stellar photosphere.