CE Gruis
CE Gruis is a faint binary star system in the constellation Grus. Its brightness changes between magnitudes 17.4 and 19.5 with a period of 108.6 minutes. It is composed of a white dwarf and donor star, locked into a synchronous orbit. In such systems, known as polars, material from the donor star does not form an accretion disc around the white dwarf because of its intense magnetic field, but rather streams directly onto it.
