  The far-ultraviolet (FUV) spectrum of the Bright Star (B8 III) in 47 Tuc (NGC
104) shows a remarkable pattern: it is well fit by LTE models at wavelengths
longer than Lyman beta, but at shorter wavelengths it is fainter than the
models by a factor of two. A spectrum of this star obtained with the Far
Ultraviolet Spectroscopic Explorer (FUSE) shows broad absorption troughs with
sharp edges at 995 and 1010 A and a deep absorption feature at 1072 A, none of
which are predicted by the models. We find that these features are caused by
resonances in the photoionization cross sections of the first and second
excited states of atomic nitrogen (2s$^2$ 2p$^3$ $^2$D$^0$ and $^2$P$^0$).
Using cross sections from the Opacity Project, we can reproduce these features,
but only if we use the cross sections at their full resolution, rather than the
resonance-averaged cross sections usually employed to model stellar
atmospheres. These resonances are strongest in stellar atmospheres with
enhanced nitrogen and depleted carbon abundances, a pattern typical of post-AGB
stars.
