R71 V-band magnitude (black squares) and radial velocities of the blue wing with respect to the red wing of the double line profiles (green squares) are shown. A sinusoidal curve with a period of 425 d, corresponding to the peak in the periodogram, is superposed in red. The photometric cycle is half the length of the spectroscopic cycle with some chaotic behavior. This may hint at period doubling; see Sect. 4.2.