A type of cataclysmic binary whose light exhibits linear and, more significantly, extremely strong circular polarization (hence the alternative name polar); abbr. AM. The polarization varies smoothly over the orbital period. Such systems consist of a K–M dwarf and a strongly magnetic compact object, accretion taking place down an accretion column over the latter's magnetic poles. The compact star's rotation is synchronized with the orbital period. Optical variations are in the form of flickering, with amplitudes up to 4–5 mag. The type star also exhibits X-ray variability.
Subjects: Astronomy and Astrophysics.