Dependence of the shape of the O – C and the period of the binary on the dataset considered. Top panel: O – C signal produced using four different datasets that mimic available observational data. Data point colors correspond to different datasets and horizontal lines at the top help to identify the corresponding observational baseline (ΔT). Bottom panel: determination of the binary period from the linear ephemeris as a function of the dataset. The horizontal solid and dashed lines represent the values of P_bin given by Bours (2015) and O’Donoghue et al. (2003), respectively. P_bin changes depending on the dataset selected.