Ab. Kaye et Dr. Gies, ON THE LINE-PROFILE VARIATIONS AND NONRADIAL PULSATION MODES OF ZETA-TAURI (HD-37202), The Astrophysical journal, 482(2), 1997, pp. 1028-1037
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.