Photometric and spectral index time series. Significant signals are marked. We show the full dataset (left panels) and their periodograms for longer periods (>50 d, middle panels) and for all periods (right panels). The grey vertical dashed lines mark the significant peaks. We show the period of the planet in green and the rotational period of the star at 140±10d in blue. For the combined MEarth data, we show the different individual sets in colours. The red dashed horizontal lines show the FAP levels of 10, 1, and 0.1%.