Hydrogen and helium features in magnetic white dwarfs

The formation of spectral features of hydrogen and helium atoms in white dwarfs having magnetic fields on the order of gauss is investigated using a Milne-Eddington type schematic model atmosphere. Several examples are presented to illustrate the effects of varying the magnitude and orientation of the stellar dipole magnetic field. Results indicate that dipofe fields on the order of 108 gauss are possible mechanisms for the production of DC-type white-dwarf spectra. While the spectrum of the magnetic white dwarf Grw + cannot be identified as that of either hydrogen or helium in a field of less than 108 gauss, preliminary results indicate that a somewhat larger field may be responsible. Subject headings: line profiles - magnetic stars - white-dwarf stars - Zeeman effect