AR Sco is a curious interacting binary star, depicted in this artist's impression. The system consists of a red dwarf (left), distorted in shape due to the gravity of its companion, a highly magnetized white dwarf (right). The system is somewhat like a so-called intermediate polar ??in which gas is transferred (accreted) from the red- to the white dwarf, resulting in the emission of pulsed radiation at the spin period of the latter. But in the case of AR Sco, no accretion is detected. The white dwarf's magnetic poles each emit a beam of light, like from a lighthouse, which illuminates the surface of the red dwarf and causes its atmosphere to accelerate electrons