Abstract
The analysis of IUE spectra of the B9 SiCrEu star HD 9996 recorded by the SWP and the LWP camera on board the International Ultraviolet Explorer collected at two phases of its very long rotational period (separated by Δϕ = 0.40), reveals large variations of the far and mid ultraviolet flux. The FUV flux seems to vary in opposition with the optical brightness recorded by the Fine Error Sensor near the V band. At ultraviolet maximum, the lines of Mg ii, Cr ii and Fe ii are definitely stronger than at minimum, which suggests that these elements are distributed in a non uniform manner on the stellar disk with large horizontal gradients. However, the changing aspect of the magnetic field between the two rotational phases observed could also cause part of the ultraviolet variability.
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