The O–C diagram for mid-transit times of WASP-10 b. The mid-transits published in the literature are marked with open symbols. The filled ones denotes new mid-transit times determined by us. The periodic signal predicted by Maciejewski et al. (2011) is sketched with a continuous line. The dashed line shows the refined linear ephemeris and the dotted one marks the linear ephemeris provided by Dittmann et al. (2010).