EXPLORING THE PECULIAR MAGNETIC-FIELD OF FEIGE-7

We present time-resolved, high signal-to-noise intensity spectra for the magnetic white dwarf Feige 7. On the basis of these data, we show, using computer models for magnetic stars, that the magnetic field in Feige 7 cannot be represented by a centered dipole geometry. We find that a good approximation to the field is a dipole of strength 35 MG displaced by 0.15 white dwarf radii from the stellar center, viewed at different angles as the star rotates. Furthermore, we find it necessary to use a model with variable surface abundances of hydrogen and helium to reproduce the variation, due to stellar rotation, in the Zeeman absorption lines of these elements.