Delta Cephei

Delta Cephei is a quadruple star system in the northern constellation of Cepheus, the King. Its name is a Bayer designation that is Latinized from δ Cephei, and abbreviated Delta Cep or δ Cep. Based on parallax measurements, it is located approximately 890 light-years away from Earth. At this distance, the visual magnitude of the star is diminished by 0.23 as a result of extinction caused by gas and dust along the line of sight. It is the prototype of the Cepheid variable stars that undergo periodic changes in luminosity.