Phase-resolved Far-Ultraviolet Hubble Space Telescope Spectroscopy of the Peculiar Magnetic White Dwarf RE J0317-853

Abstract

We present phase-resolved, far-UV Hubble Space Telescope Faint Object Spectrograph spectra of the rapidly rotating, highly magnetic white dwarf RE J0317-853. Using these data, we construct a new model for the magnetic field morphology across the stellar surface. From an expansion into spherical harmonics, we find that the range of magnetic field strengths present is 180-800 MG. For the first time, we could identify an absorption feature present at certain phases at ~1160 Å as a ``forbidden'' 1s₀-->2s₀ component, because of the combined presence of an electric and magnetic field.