POLARIZATION AND AXIAL ROTATION OF THE MAGNETIC WHITE-DWARF GD-229

Results of new polarimetric observations of the magnetic white dwarf G D 229 carried out in 1994 are reported. A comparison of these results with previously published results has revealed long-term variations in the linear and circular polarization on a time scale of similar to 10 yr. To interpret this variability, two fundamental possibilities are explored: very slow axial rotation and precession. Based on an analysi s of the polarimetric data for GD 229, we have obtained an approximate estimate of the period of the variations. This period is shown to be greater than or equal to 80 yr.