Upper panel: Light curve of KIC 6876668. The solid black line corresponds to the 20-d moving average. Medium and bottom panels: LS analysis of the light curve for the whole frequency range (medium panel) and for the period range [30 d, 90 d] (bottom panel). Black arrows indicate the possible peaks of short-term cycles (with corresponding periods in days). The broad peaks around 0.18−0.2 d⁻¹ show the rotation period of the star. The solid and dashed light blue lines give the background power level and the 10⁻⁶ FAP level, respectively. The vertical grey lines mark the separation between the frequency bins used to the determine the background power spectrum.