Cepheus (constellation)

Coordinates: Sky map 22h 00m 00s, +70° 00′ 00″
Source: Wikipedia, the free encyclopedia.
Cepheus
Constellation
27th)
Main stars7
Bayer/Flamsteed
stars		43
Stars with planets1
Stars brighter than 3.00m1
Stars within 10.00 pc (32.62 ly)3
Brightest starα Cep (Alderamin) (2.45m)
Messier objects0
Meteor showers0
Bordering
constellations		Cygnus
Lacerta
Cassiopeia
Camelopardalis
Draco
Ursa Minor
Visible at latitudes between +90° and −10°.
Best visible at 21:00 (9 p.m.) during the month of November.

Cepheus is a

Cepheus, a king of Aethiopia in Greek mythology. It is one of the 48 constellations listed by the second century astronomer Ptolemy
, and it remains one of the 88 constellations in the modern times.

The constellation's brightest star is

largest stars known. In addition, Cepheus also has the hyperluminous quasar S5 0014+81, which hosts an ultramassive black hole in its core, reported at 40 billion solar masses, about 10,000 times more massive than the central black hole of the Milky Way, making this among the most massive black holes currently known.[2][3]

History and mythology

Cepheus was the

Cassiopeia and was the father of Andromeda, both of whom are immortalized as modern day constellations along with Cepheus.[4]

Features

See also: List of stars in Cepheus
The constellation Cepheus as it may be seen by the naked eye

orange giant or subgiant[7] and a red dwarf.[8] The primary component hosts one exoplanet, Gamma Cephei Ab (Tadmor).[9] Delta Cephei is a yellow-hued supergiant star 980 light-years from Earth and the prototype of the class of the Cepheid variables. It was discovered to be variable by John Goodricke in 1784. It varies between 3.5m and 4.4m over a period of 5 days and 9 hours. The Cepheids are a class of pulsating variable stars; Delta Cephei has a minimum size of 40 solar diameters and a maximum size of 46 solar diameters. It is also a double star; the primary star also has a wide-set blue-hued companion of magnitude 6.3.[10]

There are three

eclipsing binary, but the eclipses, which occur every 20.3 years, are too faint to be observed with the unaided eye. The third, Zeta Cephei, is not as large as Mu Cephei and VV Cephei with a diameter only 94 times that of the Sun (comparable to the orbit of Mercury),[12] and has an apparent magnitude of 3.35.[13]

There are several prominent double stars and binary stars in Cepheus. Omicron Cephei is a binary star with a period of 800 years. The system, 211 light-years from Earth, consists of an orange-hued giant primary of magnitude 4.9 and a secondary of magnitude 7.1. Xi Cephei is another binary star, 102 light-years from Earth, with a period of 4,000 years. It has a blue-white primary of magnitude 4.4 and a yellow secondary of magnitude 6.5.[11]

Kruger 60 is an 11th-magnitude binary star consisting of two red dwarfs. The star system is one of the nearest, being only 13 light-years away from Earth.

Cepheus C & B Regions – Spitzer Space Telescope (30 May 2019)

Deep-sky objects

NGC 7354 is a planetary nebula located in the constellation Cepheus[14]
  • 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 ten supernovae have been observed, more than in any other galaxy. It is sometimes called the Fireworks Galaxy.[15][16]
  • IC 469 is another spiral galaxy, characterized by a compact nucleus, of oval shape, with perceptible side arms.
  • The nebula NGC 7538 is home to the largest-yet-discovered protostar.[17]
  • NGC 7023 is a reflection nebula with an associated star cluster (Collinder 429); it has an overall magnitude of 7.7 and is 1,400 light-years from Earth. The nebula and cluster are located near Beta Cephei and T Cephei.[18]
  • S 155, also known as the Cave Nebula,[19] is a dim and very diffuse bright nebula within a larger nebula complex containing emission, reflection, and dark nebulosity.
  • The quasar 6C B0014+8120 is one of the most powerful objects in the universe, powered by a supermassive black hole which is as massive as 40 billion Suns.[20]

Visualizations

Cepheus as depicted in Urania's Mirror, a set of constellation cards published in London, c. 1825

Cepheus is most commonly depicted as holding his arms aloft, praying for the deities to spare the life of Andromeda. He also is depicted as a more regal monarch sitting on his throne.[4]

Equivalents

In

Purple Forbidden enclosure (紫微垣, Zǐ Wēi Yuán) and the Black Tortoise of the North
(北方玄武, Běi Fāng Xuán Wǔ).

Namesakes

USS Cepheus (AKA-18), named after the constellation

See also

References

  1. ^ a b "Cepheus, constellation boundary". The Constellations. International Astronomical Union. Retrieved 15 February 2014.
  2. S2CID 40214759
    . This paper does acknowledge the possibility of an optical illusion that would cause an overestimation of the mass.
  3. S2CID 14438667
    .
  4. ^ a b Staal 1988, pp. 14–18
  5. ISSN 0004-6361
    .
  6. Bibcode:1995yCat.5050....0H
    .
  7. S2CID 123149047
    .
  8. ISSN 0004-6361
    .
  9. ^ "First Discoveries: Gamma Cephei A b". exoplanets.nasa.gov. Retrieved January 29, 2024.
  10. ^ Ridpath & Tirion 2001, pp. 112–115.
  11. ^ a b c Ridpath & Tirion 2001, pp. 112–113.
  12. ISSN 0004-6256
    .
  13. ISSN 0004-637X
    .
  14. ^ "Smoky Shells". ESA/Hubble Picture of the Week. Retrieved 13 December 2012.
  15. ^ Michaud, Peter (1 January 2015). "Gemini Observatory Welcomes 2005 with Release of Galactic Fireworks Image". NASA. Retrieved 2017-10-15.
  16. ^ Boen, Brooke (20 May 2015). "NGC 6946: The 'Fireworks Galaxy'". NASA. Retrieved 2016-12-08.
  17. S2CID 119284322
    .
  18. ^ Levy 2005, p. 107.
  19. ISBN 9781441903266
    .
  20. S2CID 14438667
    . 17:53:24 GMT.

External links

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