Detrended S_MWO time series of the observing season 2015−16. Upper panel: sinusoidal fit with a the period of 59.5 days (solid curve); best fit with a 121.8-day cycle estimated from the data until 2463 [HJD-2 455 000] (dotted curve); ad hoc fit with a sine curve of 120.5 days with adapted amplitude and phase as well as phase shift (dashed and dash-dotted curve). See text for details. Lower panel: residuals of the sinusoidal fit with the period of 59.5 days.