{\it IUE} Observations of Rotational Modulation of OB Star Winds
Session 22 -- Stellar Spectroscopy, Atmospheres, Models, Intrinsic Variables, Theory, Part II
Display presentation, Tuesday, June 13, 1995, 9:20am - 6:30pm

## [22.17] {\it IUE} Observations of Rotational Modulation of OB Star Winds

D. Massa (ARC), R. K. Prinja (UCL), A. W. Fullerton (Max-Planck-Institut, M\"unchen)

Wind varibaility in OB stars was first detected by Snow (1977) and York et al. (1977), and a connection between rotation and wind activity was established by Prinja (1988) and Henrichs, Kaper, \& Zwarthoed (1988). However, the origin of this connection remained unknown. To uncover the nature of the rotation connection, an IUE observing proposal with 33 Co-Investigators was drafted at the workshop on Instability and Variability of Hot-Star Winds held at Isle-aux-Coudres, Quebec in 1993. The goal of this program was to follow 3 stars for several rotations to determine whether the rotation connection is correlative or causal. The stars selected for monitoring all had rotation periods $\le$ 5 days. They were: HD 50896 (WN5), HD 64760 (B0.5 Ib), and HD 66811 ($\zeta$ Pup, O4 If (n)). During 16 days of nearly continuous observations in January of 1995, 444 high dispersion IUE spectra of these stars were obtained. We will present an overview of the results of the campaign and provide a detailed discussion of the results for HD 64760.