Voyager observations of Zeta Tau

Two Voyager observations of Zeta Tau, a well-known Be/shell star of spectral type B1 IVe and vsin(i) = 220 km/s, separated by 503 days are presented and discussed. The observations show that in the spectral region shortward of Lyman-alpha, the 950-1150 A flux increased by about 40 percent, while in the region longward of 1300 A the flux increased by about 30 percent. Changes in features at 975 A and at 1020 A also appear. The observed change in the continuum flux is probably associated with a change in the effective temperature of the underlying B star, though change in the ubiquitous Fe II lines cannot be ruled out as the cause. The line variations are consistent with IUE spectra of Zeta Tau taken during the same time period.