Light curves extracted from CHEOPSim image time series, using photometric extraction performed by the data reduction pipeline that will be used with real CHEOPS data, for an Earth-sized planet with a 50 day orbital period orbiting a V = 6 G2V star (top), and for the same planet orbiting a V = 9 G2V star (bottom). For the V = 6 case, the exposure duration is 0.5 s, and exposures are stacked with 40 exposures per stack. For the V = 9 case, the exposure duration is 10 s, and exposures are stacked with six exposures per stack. Gaps in the light curves correspond to interruptions due to Earth occultation (once per CHEOPS orbit). The simulated photon flux incident on the telescope is shown in each case by the red line. Stellar granulation was not simulated, resulting in smooth curves.