Cepheus (constellation)

Categories: Cepheus constellation

Cepheus
Image:Cepheus constellation map.png click for larger image
Abbreviation	Cep
Genitive	Cephei
Symbology	The King/ King Cepheus
Right ascension	22 h
Declination	+70°
Area	588 sq. deg. Ranked 27th
Number of stars (magnitude < 3)	1
Brightest star	α Cep (Alderamin) (App. magnitude 2.44)
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 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.

Contents 1 Notable features 2 Notable deep sky objects 3 Mythology 4 Stars 5 External links

Notable features

γ Cephei is a binary star approximately 50 light years away from Earth. The system consists of an orange star and a red dwarf. Due to the precession of the equinoxes, γ Cephei will be the pole star between 3000 and 5200 A.D., with the closest approach to the north celestial pole around 4000 A.D.

δ Cephei is the prototype Cepheid variable. It was discovered to be variable by John Goodricke in 1784. It varies between apparent magnitudes 3.5 and 4.3 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 magnitudes 3.4m and 5.1m 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 (VV Cep) is also variable, ranging from magnitudes 4.8m and 5.4m over a period around 20 years. The third red supergiant is HR 8164, whose apparent magnitude is 5.66m.

Kruger 60 is an 10th magnitude binary star consisting of two red dwarfs. Its components are known as Kruger 60 A and Kruger 60 B. The star system is 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. NGC 6946 is a spiral galaxy in which seven supernovae have been observed, more than in any other galaxy.

Mythology

When including fainter stars, visible to the naked eye, Cephus 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.

Stars

Stars with proper names:

• (5/α Cep) 2.45 Alderamin [Alderaimin]

  < الذراع الأيمن að-ðirā^{c al-’ayman} The right arm

• (8/β Cep) 3.23 Alfirk [Alphirk]

  < الفرقة al-firqah The flock

• (35/γ Cep) 3.21 Alrai [Arrai, Errai, Er Rai] – has a planet

  < الراعي ar-rā^cī The shepherd

• (2/θ Cep) (or Al Kidr, see η Cep) 4.21

• (23/η Cep) 4.18 Al Kidr

  < القدر al-qidr The bowl

• (μ Cep) 4.23 Garnet Star or Erakis

  < الراقص ar-rāqiş The dancer

• (17/ξ Cep) 4.26 Kurhah [Alkurah, Alkurab, Al Kirdah]

  < القُرّة al-qurrah The blaze [horse's brow]

• (29/ρ Cep) – double 5.5 & 5.83 Al Kalb al Rai

  < كلب الراعي kalb ar-rā^cī [The] dog of the shepherd

Stars with Bayer designations:

27/δ Cep – double 4.07, 6.31; pulsating variable, Cepheid variable prototype; 23/ε Cep 4.18; 21/ζ Cep 3.39; 3/η Cep 3.41; 32/ι Cep 3.50; 1/κ Cep 4.38; 22/λ Cep 5.05; 10/ν Cep 4.25; 34/ο Cep 4.75v33/π Cep 4.41; υ Cep 6.90; υ¹ Cep 4.52

Stars with Flamsteed designation:

4 Cep 5.59; 6 Cep 5.19; 7 Cep 5.42; 9 Cep 4.76; 11 Cep 4.55; 12 Cep 5.53; 13 Cep 5.74; 14 Cep 5.55; 15 Cep 6.69; 16 Cep 5.04; 18 Cep 5.26; 19 Cep 5.07; 20 Cep 5.27; 24 Cep 4.79; 25 Cep 5.75; 26 Cep 5.52; 28 Cep 5.83; 30 Cep 5.19; 31 Cep 5.08

Other notable stars:

• Kruger 60 – double; nearby

• Kruger 60 A 9.85
• Kruger 60 B 11.30 – flare star

Constellations listed by Ptolemy

Andromeda | Aquarius | Aquila | Ara | Argo Navis | Aries | Auriga | Boötes | Cancer | Canis Major | Canis Minor | Capricornus | Cassiopeia | Centaurus | Cepheus | Cetus | Corona Australis | Corona Borealis | Corvus | Crater | Cygnus | Delphinus | Draco | Equuleus | Eridanus | Gemini | Hercules | Hydra | Leo | Lepus | Libra | Lupus | Lyra | Ophiuchus | Orion | Pegasus | Perseus | Pisces | Piscis Austrinus | Sagitta | Sagittarius | Scorpius | Serpens | Taurus | Triangulum | Ursa Major | Ursa Minor | Virgo

The 88 modern Constellations

Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Boötes | Caelum | Camelopardalis | Cancer | Canes Venatici | Canis Major | Canis Minor | Capricornus | Carina | Cassiopeia | Centaurus | Cepheus | Cetus | Chamaeleon | Circinus | Columba | Coma Berenices | Corona Australis | Corona Borealis | Corvus | Crater | Crux | Cygnus | Delphinus | Dorado | Draco | Equuleus | Eridanus | Fornax | Gemini | Grus | Hercules | Horologium | Hydra | Hydrus | Indus | Lacerta | Leo | Leo Minor | Lepus | Libra | Lupus | Lynx | Lyra | Mensa | Microscopium | Monoceros | Musca | Norma | Octans | Ophiuchus | Orion | Pavo | Pegasus | Perseus | Phoenix | Pictor | Pisces | Piscis Austrinus | Puppis | Pyxis | Reticulum | Sagitta | Sagittarius | Scorpius | Sculptor | Scutum | Serpens | Sextans | Taurus | Telescopium | Triangulum | Triangulum Australe | Tucana | Ursa Major | Ursa Minor | Vela | Virgo | Volans | Vulpecula

External links

• The Deep Photographic Guide to the Constellations: Cepheus
• The clickable Cepheusca:Cefeu (constel·lació)

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