A constellation of the north polar region of the sky, representing King Cepheus of Greek mythology. Its brightest star is Alpha Cephei (Alderamin), but its best-known star is the double Delta Cephei, the brighter component of which is the prototype Cepheid variable, ranging from magnitude 3.5 to 4.4 in a period of 5.37 days. Beta Cephei (Alfirk) is a double of unrelated stars, magnitudes 3.2 and 7.9, the brighter of which is slightly variable (see beta cepheid variable). Mu Cephei is a variable red supergiant known as the Garnet Star.
Subjects: Astronomy and Astrophysics.