Cepheus (constellation)

Cepheus

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List of stars in Cepheus
Abbreviation:	Cep
Genitive:	Cephei
Symbology:	The King/King Cepheus
Right ascension:	22 h
Declination:	+70°
Area:	588 sq. deg. (27th)
Main stars:	7
Bayer/Flamsteed stars:	35
Stars known to have planets:	1
Bright stars:	1
Nearby stars:	5
Brightest star:	α Cep (Alderamin) (2.44m)
Nearest star:	Kruger 60 (13.15 ly)
Messier objects:	0
Meteor showers:	None
Bordering constellations:	Ursa Minor Draco Cygnus Lacerta Cassiopeia Camelopardalis
Visible at latitudes between +90° and −10° Best visible at 21:00 (9 p.m.) during the month of November

Cepheus (pronounced /ˈsiːfiəs/ or /ˈsiːfjuːs/) is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. It is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy.

Notable features

γ Cephei is a binary star approximately 50 light years away from Earth. The system consists of an orange subgiant and a red dwarf. Due to the precession of the equinoxes, γ Cephei will be the pole star between 3000 and 5200 AD, with the closest approach to the north celestial pole around 4000 AD. The primary component is orbited by a planet. δ Cephei is the prototype Cepheid variable. It was discovered to be variable by John Goodricke in 1784. It varies between 3.5^m and 4.3^m over a period around 5.4 days. There are three red supergiants in the constellation that are visible to the naked eye. μ Cephei is known as Herschel's Garnet Star due to its deep red colour. It is a semiregular variable star that varies between 3.4^m and 5.1^m over a period of 730 days. The star is around 11.8 AU in radius. If it were placed at the centre of our Solar System, it would extend to the orbit of Saturn. Like μ Cep, VV Cephei is also variable, ranging from 4.8^m and 5.4^m over a period around 20 years. The third red supergiant is HR 8164, whose apparent magnitude is 5.66^m. Each of the stars are among the largest known. Kruger 60 is a 10th magnitude binary star consisting of two red dwarfs. The star system is one of the nearest being only 13 light years away from Earth.

Notable deep sky objects

NGC 188 is an open cluster that has the distinction of being the closest open cluster to the north celestial pole, as well as one of the oldest known open clusters. The Fireworks Galaxy (NGC 6946) is a spiral galaxy in which eight supernovae have been observed, more than in any other galaxy. The nebula NGC 7538 is home to the largest yet discovered protostar.

Mythology

When including fainter stars, visible to the naked eye, Cepheus appears as a man with a crown (upside down with respect to the ecliptic). Together with other constellations nearby (Andromeda, Perseus, Cassiopeia, and possibly Pegasus), and the constellation Cetus below Cepheus, this may be the source of the myth of the Boast of Cassiopeia, with which it is usually identified.

References

• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.

External links

• The Deep Photographic Guide to the Constellations: Cepheus
• Star Tales – Cepheus