Data from the V-band between MJD 58283 and MJD 58391 folded with the value of the frequency f reported in Table 1. The dotted black line is the sinusoidal fitted model with the corresponding 3σ confidence uncertainty shown as a grey shaded area. Some residuals can be seen in the plot and are caused by the data within certain time intervals where the oscillation is not perfectly visible or slightly out of phase, as can be seen from Fig. 7.