Discovery of Circularly Polarized Light from a White Dwarf

Strong circular polarization, 1-3 percent, has been discovered in visible light from the semi-DC 'peculiar' white dwarf Grw+70°08247. This is the first such observation on any white dwarf, and is taken as indicating a strong magnetic field. From the theory of gray-body magnetoemissivity, to which the wavelength dependence of the circular polarization would appear to conform, one estimates a mean projected B field of 1 × 10⁷ gauss.