Rotational Modulation of B Supergiant Winds

We present a 30 day IUE time series of the BO Ia star HD 91969, a member of the Carina open cluster NGC 3293. We show that wind lines which probe more deeply into the wind vary more regularly and that the lowest stages of ionization and the Si III λλ 1300 triplets have a dominant period of ~ 7.9 days. The photospheric lines (primarily Fe Iv) also vary regularly, except with a period of 3.95 — half the dominant wind line period. Further, the photospheric lines do not vary at 7.9 days. While these results show a clear relationship between the wind and photospheric variability, the physical nature of the connection remains elusive.