Tags: Star.
Omicron Cephei (Omicron Cep ο Cephei ο Cep) is a binary star in the constellation of Cepheus. It consists of a less massive K-type main sequence star in orbit with a more massive G-type giant star. The overall apparent visual magnitude of the system is 4.75.The pair was first determined to be binary by F. G. W. Struve in 1832. Since then the secondary has been seen to revolve approximately 45 degrees around the primary.