1996A&A...306..899B

The Position Sensitive Proportional Counter (PSPC) onboard the ROSAT satellite was used to monitor ζ Pup for 56651seconds spread over 11days in 1991 October. During the first 8days, 592 high-resolution Hα profiles were also obtained simultaneously. In a detailed time series analysis we investigate the X-ray observations and the Hα line profiles for variability. We find a 1.44c/d (cycles/day) modulation both in the Hα line profiles as well as in the X-ray band pass between 0.9 and 2.0keV; the amplitude of the X-ray variability amounts to ±6%. Thus, our observations provide evidence for periodic variations in the wind density at the base of the wind of ζ Pup.