ON THE LINE-PROFILE VARIATIONS AND NONRADIAL PULSATION MODES OF ZETA-TAURI (HD-37202)

We present high signal-to-noise ratio spectra of the H alpha, H beta, and He I 1 lambda lambda 4921,6678 spectral lines of the line profile variable and binary star zeta Tauri obtained between 1986 and 1988 usi ng the University of Texas McDonald Observatory 2.1 m telescope. For i ntervals of sufficiently dense observation, we calculate power spectra for the time series defined at each point in the line profile in orde r to search for periodic variability. A single, prominent signal corre sponding to a period of 0.777 +/- 0.002 days dominates the power spect ra over most of the profiles of each of the four lines. Based on the p ower distribution across the profile at this signal frequency, we argu e that the only plausible explanation for these variations is photosph eric nonradial pulsation (g-mode pulsations of degree l = -m = 2). We find no evidence for accompanying higher order NRP modes; however, the spectra do show weak, narrow, and nonperiodic features that cross the profiles on timescales similar to the NRP mode.