THE IUE MEGA CAMPAIGN - THE ROTATIONALLY MODULATED WIND OF ZETA-PUPPIS

We discuss 16 days of intensive IUE observations of the Si Iv doublet (lambda 1400) in the spectrum of the O4 I(n) f star zeta Pup. The data show continuous variability throughout the greater part of the bluesh ifted absorption. Time series analysis of these data reveals significa nt power at periods of 19.2 hr and 5.2 days, which we identify with th e mean recurrence time of ''discrete absorption components'' (DACs) an d the photospheric rotation period, respectively. These results indica te that the wind has a global longitudinal asymmetry (approaching a fa ctor 2 in optical depth), possibly associated with large-scale magneti c structures, but suggest that the DACs are not directly associated wi th specific stellar longitudes in this star. There is no significant p ower in the lines at the 8.5 hr period identified in photospheric abso rption-line variability, nor at the 16.7 hr period reported in X-ray o bservations.