Folding search of periodicities between 22.78 and 26.92 d in the ASM light curve, including all the SSCs (top panel) and including only SSC 2 and 3 (bottom panel), respectively. We adopted 16 phase-bins per period for the trial folded light curves and a resolution in the period search of 43.2 s (top panel) and 86.4 s (bottom panel). The maximum of χ² is observed at 24.53 d (vertical red line) in both curves. The vertical solid green line indicates a possible periodicity at 24.12 d. The vertical solid blue and dashed blue lines indicate the period of 24.27 ± 0.03 d suggested by Corbet et al. (2010). The bin time is 1.53 d.