NOTABLE STARS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z           HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site Delta Cephei Delta Cephei. Image: © T. Credner & S. Kohle, AlltheSky.com The second Cepheid variable to be identified and the prototype for the category known as Type I Cepheids, or Delta Cephei stars. With a change in apparent magnitude of 3.5 to 4.4 over a period of 5.366 days, Delta Cep's entire range of variability can be followed with the naked eye. At a declination of +58°, Delta makes a perfect target for northern observers, especially those who see Cepheus as a circumpolar constellation. Also, it lies conveniently between two bright stars that shine close to each end of its range of variability: Zeta Cep (magnitude 3.6) and Epsilon Cep (magnitude 4.2). For those observing with binoculars or a modest telescope, Delta Cep's companion stars can be discerned. A seventh magnitude mate is located 41" from the variable itself and is thought to be physically associated with it. A second nearby star of 13th magnitude, located 20.9" from Delta, is most likely a line-of-sight object. visual magnitude 4.07 (mean) absolute magnitude -3.47 spectral type G2Ib temperature 5,500–6,800 K luminosity 2,000 Lsun mass 5 Msun distance 890 light-years (273 pc) position R.A. 22h 29m 12s, Dec. +58° 25' 08" other designations 27 Cep, HR 8571, BD +57°2548, HD 213306, SAO 34508, FK5 847, AAVSO 2225+57, IRAS 22273+5809, HIP 110991 Related categories    • NOTABLE STARS    • VARIABLE STARS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP