Impact of noise model errors on the significance levels. Left: Lomb–Scargle periodogram of the α CenB RV residuals. The peak at 3.2 days is shown by the gray vertical arrow. Solid lines are the mean p-values estimated without a model error. The p-value at t: = p(3.2 d) = 24.48 is within the 90% interval [0.1%, 0.7%]. Dotted lines are the mean p-values estimated with a model error (see text). The p-value at t = 24.48 this time is within the 90% interval [59.5%, 64.7%]. Right: distribution of the period index where the maximum periodogram value was found in row 15 of algorithm 2 (zoom at periods <20 days). The standard version of the 3SD procedure (simulating the situation without a model error) is shown in the top panel, and the hybrid version (detection process run with a model error) is shown in the bottom panel. A bias toward specific periods is visible in the bottom panel: the model error leaves residuals in which periodicities are imprinted.