AR Andromedae
AR Andromedae is a dwarf nova of the SS Cygni type in the constellation Andromeda. Its typical apparent visual magnitude is 17.6, but increases up to 11.0 magnitude during outbursts. The outbursts occur approximately every 23 days.
System
Dwarf novae systems are made up by a classical star with a white dwarf companion. By measuring the Doppler shift of spectral lines, it was found to have an orbital period of 3.91 hours. The accretion disk around white dwarf seems to be axisymmetric and devoid of structure.Variability
AR Andromedae was first listed as a variable star by Frank Elmore Ross in 1929, based on observations in 1907 and 1927. It was initially classified as a Mira variable star. In 1934 it was given the variable star designation AR Andromedae.The light emitted by dwarf novae like AR Andromedae comes entirely from the accretion disc and the white dwarf; the luminosity increase during outbursts is typically induced by a variation in the accretion rate of the white dwarf. The outbursts are unusually frequent, with 19 outbursts detected by 2016.