Jump to content

Perseus (constellation)

Coordinates: Sky map 03h 00m 00s, +45° 00′ 00″
This is a good article. Click here for more information.
From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Alphathon (talk | contribs) at 23:55, 14 August 2013 (→‎Stars). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

For other meanings, see Perseus (disambiguation).

Perseus
Constellation
Perseus
List of stars in Perseus
AbbreviationPer
GenitivePersei
Pronunciation/ˈpɜːrsiːəs/ or /ˈpɜːrsjuːs/;
genitive /ˈpɜːrsiː.aɪ/
SymbolismPerseus
Right ascension3
Declination+45
QuadrantNQ1
Area615 sq. deg. (24th)
Main stars19
Bayer/Flamsteed
stars		65
Stars with planets7
Stars brighter than 3.00m5
Stars within 10.00 pc (32.62 ly)0
Brightest starα Per (Mirfak) (1.79m)
Messier objects2
Meteor showersPerseids
September Perseids
Bordering
constellations		Aries
Taurus
Auriga
Camelopardalis
Cassiopeia
Andromeda
Triangulum
Visible at latitudes between +90° and −35°.
Best visible at 21:00 (9 p.m.) during the month of December.

Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union. Located in the northern celestial hemisphere, it lies near several other constellations from the legend of Perseus, including Andromeda (the maiden he rescued), Cetus (the sea monster he slew) and Cepheus and Cassiopeia (Andromeda's royal parents).

The brightest star in the constellation is the yellow-white supergiant Alpha Persei, called Mirfak, which shines at magnitude 1.79. The most notable star, however, is the famous variable star Algol (Beta Persei), linked with ominous legends on account of its variability, apparent to the naked eye. GK Persei was a nova which brightened to magnitude 0.2 in 1901, making it briefly one of the brightest stars in the sky. The constellation also gives its name to the Perseus Cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. The constellation hosts the radiant of the annual Perseids meteor shower, one of the most prominent meteor showers in the sky.

History and mythology

See also: Perseus
Constellation drawing of Perseus
Perseus carrying the head of Medusa the Gorgon, as depicted in Urania's Mirror,[1] a set of constellation cards published in London c.1825

The Greek constellation may be a derivative of the Babylonian constellation known as the Old Man (MUL.SHU.GI) which was associated with East in the MUL.APIN, an astronomical compilation dating to around 1000 BCE.[2] In Greek mythology, Perseus was the son of Danae, who was sent by King Polydectes to bring the head of Medusa the Gorgon as a wedding gift, whose gaze was so ugly that it turned every living creature to stone. Perseus was able to slay her in her sleep, and Pegasus and Chrysaor appeared from her body.[3] Perseus then continued to the land of King Cepheus, whose daughter Andromeda was going to be sacrificed to Cetus the sea monster. He used the Gorgon's head to rescue the princess Andromeda from Cetus by turning Cetus to stone.[4] Perseus then turned Polydectes and his followers to stone using Medusa's head, and appointed Dictys the fisherman king.[3] Perseus and Andromeda wed and had six children.[4] In the sky, Perseus is near the constellations Andromeda, Cepheus, Cassiopeia (Andromeda's mother), Cetus, and Pegasus.[3]

In non-Western astronomy

Four Chinese constellations are contained in the area of the sky now containing Perseus. T'ien-tchouen, the Celestial Boat, was the third paranatellon of the third house of the White Tiger of the West, representing the boats that Chinese people were reminded to build in case of a catastrophic flood season. Tsi-choui, the Swollen Waters, was the fourth paranatellon of the aforementioned house, representing the potential of unusually high floods during the end of August and beginning of September at the beginning of the flood season. Ta-ling, the Great Trench, was the fifth paranatellon of that house, representing the trenches where criminals executed en masse in August were interred. The pile of corpses prior to their interment was represented by Tsi-chi (Algol), the sixth paranatellon of the house.[5]

The Double Cluster, h and χ Persei, had special significance in Chinese astronomy. Known as Hsi and Ho, the two clusters represented two astronomers who failed to predict a total solar eclipse and were beheaded thereafter.[5]

In Polynesia, Perseus was not commonly recognized as a separate constellation; the only people that named it were the people of the Society Islands, who called it Faa-iti, meaning "Little Valley".[6] Algol may have been named Matohi by the Maori people, but the evidence for this identification is disputed. Matohi ("Split") occasionally came into conflict with Tangaroa-whakapau over which of them should appear in the sky, the outcome affecting the tides. It matches the Maori description of a blue-white star near Aldebaran but does not disappear as the myth would indicate.[7]

Characteristics

Perseus is bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis and Cassiopea to the north, and Andromeda and Triangulum to the west. Covering 615 square degrees, it ranks twenty-fourth of the 88 constellations in size. It appears prominently in the northern sky during the Northern Hemisphere's spring and 19 stars form the constellation's main asterism. The constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of 26 sides. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 01h 29.1m and 04h 51.2m , while the declination coordinates are between 30.92° and 59.11°.[8] The constellation's three-letter abbreviation, as adopted by the International Astronomical Union in 1922, is "Per".[9]

Notable features

Night sky photograph of the constellation Perseus
The constellation Perseus as it can be seen by the naked eye

Stars

See also: List of stars in Perseus

Algol (from the Arabic Ra's al-Ghul, which means The Demon's Head), also known by its Bayer designation Beta Persei, is the best-known star in Perseus. Representing the eye of the Gorgon Medusa in Greek mythology, it was called Rosh ha Satan ("Satan's Head") by the Hebrew people, who saw Algol as representing Lilith. It is 92.8 light-years from Earth and varies in magnitude from a minimum of 3.5 to a maximum of 2.3 with a period of 2.867 days.[10] It is a triple star. The brightest component is spectral type B8V,[11] the secondary component is type K0IV,[12] and the tertiary component is type A7.[13] The star system is the prototype of a whole group of eclipsing binary stars named Algol variables. Another Algol variable in Perseus is AG Persei, whose primary component is a B-type main sequence star with an apparent magnitude of 6.69.[14]

Alpha Persei, also known as Mirfak (Arabic for elbow) or Algenib, is the brightest star of this constellation with an apparent brightness of 1.79. A supergiant of spectral type F5Ib located around 590 light-years away from our solar system,[15] Mirfak has 5,000 times the luminosity and 42 times the diameter of our sun. It is the brightest member of the Alpha Persei Cluster (also known as Melotte 20 and Collinder 39), which is an open cluster containing many luminous stars. Neighbouring bright stars that are members include the Be stars Delta (magnitude 3.0),[16] Psi (4.3),[17] and 48 Persei (4.0);[18] the Beta Cephei variable Epsilon Persei (2.9);[19] and the stars 29 (5.2),[20] 30 (5.5),[21] and 34 Persei (4.7).[22]

Zeta Persei, or Atik, at magnitude 2.86 is the third-brightest star in the constellation. Around 750 light-years from Earth, it is a blue-white supergiant approximately 26–27 times the radius of the sun and 47,000 times its luminosity. It is the brightest star (as seen from Earth) of another moving group of bright blue-white giant and supergiant stars, the Perseus OB2 Association or Zeta Persei Association. X Persei is a double star in this association; one component is a hot, bright star and the other is a neutron star.[23] With an apparent magnitude of 6.72, it is too dim to be seen with the naked eye even in perfectly dark conditions.[24] The system is an X-ray source and the primary star appears to be undergoing substantial mass loss.[25] Once thought to be a member of the Perseus OB2 Association,[26] Omicron Persei is a multiple star system with a combined visual magnitude of 3.85.[27] It is composed of two blue-white stars — a giant of spectral class B1.5 and main sequence star of B3 — which orbit each other every 4.5 days and are distorted into egg shapes due to their small separation. The system has a third star about which little is known. At an estimated distance of 1475 light-years, the system is now thought to lie too far from the center of the Zeta Persei group to belong to it.[28]

GRO J0422+32 is another X-ray binary in Perseus. One component is possibly a black hole, while the other is a red dwarf star. If the system does indeed contain a black hole, it would be the smallest black hole ever recorded as of 2003.[29] The system is an X-ray nova, meaning that it experiences periodic outbursts in the X-ray band of the electromagnetic spectrum.[30] GK Persei, also known as Nova Persei 1901, is a bright nova that appeared halfway between Algol and Delta Persei. Discovered on February 21, 1901 by Scottish amateur astronomer Thomas David Anderson, it peaked at magnitude 0.2, almost as bright as Capella and Vega. It faded to 13th magnitude around 30 years after its peak brightness.[31]

Xi Persei, traditionally known as Menkhib,[32] is one of the hottest bright stars in the sky, a blue giant of spectral type O7III.[33] It is one of the more massive stars, being between 26 and 32 solar masses.[33][34]

The Double Cluster contains three very large stars: S, RS, and SU Persei. All three are semiregular pulsating M-type supergiants[35][36][37] with radii of above 700 solar radii.[38] The stars are not visible to the naked eye; SU Persei (the brightest of the three) has an apparent magnitude of only 7.9,[37] only visible through binoculars. The primary component of the binary star system AX Persei is another star in an advanced phase of stellar evolution, in this case a red giant,[39] which is transferring material onto an accretion disc around a smaller star.[40] The star system is a symbiotic binary, but is unusual because the secondary star is not a white dwarf, but an A-type star.[39] The system is one of the few eclipsing symbiotic binaries.[40]

DY Persei is a variable star that is the prototype of DY Persei variables, which are carbon-rich R Coronae Borealis variables that exhibit the variability of asymptotic giant branch stars.[41] DY Persei itself is a carbon star that is too dim to see even through binoculars, with an apparent magnitude of 10.6.[42]

Seven stars in Perseus have been found to have planetary systems. V718 Persei is a star in the young open cluster IC 348 that appears to be periodically eclipsed by a giant planet every 4.7 years.[43] This has been inferred to be an object with a maximum mass of 6 times that of Jupiter and an orbital radius of 3.3 astronomical units.[44]

Deep-sky objects

Photograph of The Double Cluster
The Double Cluster (NGC 869 and NGC 884)

The Double Cluster is made up of two open clusters (NGC 869 and NGC 884), easily visible in binoculars and small telescopes. They are sometimes known as h and Chi (χ) Persei, respectively.[45][46] Both lie at distances of more than 7,000 light-years and are separated by several hundred light-years. The cluster was first recorded during the reign of the Chinese king Tsung-K'ang, who reigned during the Hsia Dynasty (2858–2146 BCE).[5] Both clusters are of approximately 4th magnitude and 0.5 degrees in diameter. The two are Trumpler class I 3 r clusters, though NGC 869 is a Shapley class f and NGC 884 is a Shapley class e cluster. These classifications indicate that they are both quite rich; NGC 869 is the richer (more dense) of the pair.[47] These clusters are both distinct from their star field and are clearly concentrated at their centers. The constituent stars, numbering over 100 in each cluster, range widely in brightness.[48] M34 is an open cluster that appears at magnitude 5.5,[49] lying at a distance of approximately 1,500 light-years[50] that contains about 100 stars scattered over an area larger than that of the full moon.[49] M34 can be resolved with good eyesight but is best viewed using a telescope at low magnifications. IC 348 is a somewhat young open cluster that is still contained within the nebula from which its stars formed. It is located about 1,027 light-years from Earth, is about 2 million years old,[51] and contains many stars with circumstellar disks.[52] Many brown dwarfs have been discovered in this cluster due to its age; since brown dwarfs cool as they age, it is easier to find them in younger clusters.[53]

There are many nebulae in Perseus. M76 is a planetary nebula, also called the Little Dumbbell Nebula.[54] It appears two arc-seconds by one arc-second across and has an apparent brightness of magnitude 10.1.[54] NGC 1499, also known as the California Nebula, is an emission nebula,[55] discovered in 1884–85 by the American astronomer Edward E. Barnard. It is a very difficult object to observe visually because its low surface brightness[56] makes it appear dimmer than comparable objects. NGC 1333 is a reflection nebula[57] and a star forming region.[58] Perseus also contains a giant molecular cloud, called the Perseus molecular cloud; it belongs to the Orion Spur and is well known for its low rate of star formation compared to other similar clouds.[59]

Perseus contains a few notable galaxies. NGC 1260 is either a lenticular or tightly-wound spiral galaxy about 76.7 megaparsecs from Earth. It contains the second brightest known object in the universe, SN 2006gy.[60] NGC 1023 is a barred spiral galaxy of magnitude 10.35 around 11.6 megaparsecs from Earth.[61] It is the principal member of the NGC 1023 group of galaxies and is possibly interacting with another galaxy.[62] The constellation also contains an interesting galaxy cluster, the Perseus Cluster (Abell 426). It is a massive galaxy cluster located 250 million light-years from Earth; at a redshift of 0.0179, it is the closest major cluster to Earth.[63] NGC 1275, a component of the cluster, is a Seyfert galaxy containing an active nucleus that produces jets of material, surrounding the galaxy with massive bubbles.[64] These bubbles create sound waves that travel through the Perseus Cluster, sounding a B flat 57 octaves below middle C.[64] This galaxy is a cD galaxy that has undergone many mergers throughout its existence, as evidenced by the "high velocity system" surrounding it (the remnants of a smaller galaxy). Its active nucleus is a strong source of radio waves.[64]

Meteor showers

The Perseids are a prominent annual meteor shower that radiate from Perseus in late summer, visible from mid-July and peaking in activity between August 9 and 14 each year. Associated with the comet Swift-Tuttle, they have been observed for about 2000 years.[65]

The September Epsilon Perseids, discovered in 2012, are a meteor shower with an unknown parent body in the Oort cloud.[66]

References

  1. ^ Ridpath, I. "Urania's Mirror c.1825 – Ian Ridpath's Old Star Atlases". Retrieved 17 July 2013.
  2. ^ Dalley, S. (1998). The Legacy of Mesopotamia. Oxford University Press. p. 128. ISBN 978-0-19-814946-0.
  3. ^ a b c Ridpath, I. "Star Tales –Perseus". Retrieved 28 July 2013.
  4. ^ a b Ridpath, I. "Star Tales –Andromeda". Retrieved 28 July 2013.
  5. ^ a b c Stall, 1988, pp. 19–26
  6. ^ Makemon, 1941, p. 203
  7. ^ Makemon, 1941, pp. 233–234
  8. ^ "Perseus, Constellation Boundary". The Constellations. International Astronomical Union. Retrieved 16 February 2013.
  9. ^ Russell, H. N. (1922). "The New International Symbols for the Constellations". Popular Astronomy. 30: 469–71. Bibcode:1922PA.....30..469R.
  10. ^ Levy, D. H. (2005). Deep Sky Objects. Prometheus Books. pp. 60–61. ISBN 1-59102-361-0.
  11. ^ "* Bet Per – Eclipsing Binary of Algol Type (Detached)". SIMBAD. Retrieved 18 February 2013.
  12. ^ "NAME ALGOL B – Star in Double System". SIMBAD. Retrieved 18 February 2013.
  13. ^ "NAME ALGOL C – Star in Double System". SIMBAD. Retrieved 18 February 2013.
  14. ^ "* AG Per – Eclipsing Binary of Algol Type (Detached)". SIMBAD. Retrieved 15 February 2013.
  15. ^ "V* Alf Per – Variable Star". SIMBAD. Retrieved 31 January 2013.
  16. ^ "* Del Per – Be Star". SIMBAD. Retrieved 31 January 2013.
  17. ^ "* Psi Per – Be Star". SIMBAD. Retrieved 31 January 2013.
  18. ^ "* c Per – Be star". SIMBAD. Retrieved 31 January 2013.
  19. ^ "V* Eps Per – Variable Star of Beta Cep Type". SIMBAD. Retrieved 31 January 2013.
  20. ^ "* 29 Per – Star". SIMBAD. Retrieved 31 January 2013.
  21. ^ "* 30 Per – Star". SIMBAD. Retrieved 31 January 2013.
  22. ^ "* 34 Per – Star". SIMBAD. Retrieved 31 January 2013.
  23. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/318236, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/318236 instead.
  24. ^ "V* X Per – High Mass X-ray Binary". SIMBAD. Retrieved 8 February 2013.
  25. ^ White, N. E.; Swank, J. H.; Holt, S. S.; Parmar, A. N. (1982). "A Comparaison of the X-ray Properties of X Persei and Gamma Cassiopeiae". Astrophysical Journal. 263 (1): 277–288. Bibcode:1982ApJ...263..277W. doi:10.1086/160502.
  26. ^ Steenbrugge, K. C.; de Bruijne, J. H. J.; Hoogerwerf, R.; de Zeeuw, P. T. (2003). "Radial Velocities of Early-Type Stars in the Perseus OB2 Association". Astronomy and Astrophysics. 402 (2): 587–605. arXiv:astro-ph/0302428. Bibcode:2003A&A...402..587S. doi:10.1051/0004-6361:20030277.
  27. ^ "V* Omi Per – Ellipsoidal Variable Star". SIMBAD. Retrieved 17 February 2013.
  28. ^ Kaler, J. B. "Atik (Omicron Persei)". Stars. University of Illinois. Retrieved 16 February 2013.
  29. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/379311, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/379311 instead.
  30. ^ Callanan, P. J.; Garcia, M. R.; McClintock, J. E.; Zhao, P.; Remillard, R. A.; Bailyn, C. D.; Orosz, J. A.; Harmon, B. A.; Paciesas, W. S. (1995). "Observations of the X-ray Nova GRO J0422+32. 1: Outburst and the decay to quiescence". Astrophysical Journal. 442 (2): 786–799. Bibcode:1995ApJ...441..786C. doi:10.1086/175402.
  31. ^ Mots & Nathanson, 1991, p. 342
  32. ^ "NAME Menkhib – Star". SIMBAD. Retrieved 16 February 2013.
  33. ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1051/0004-6361:20034594, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1051/0004-6361:20034594 instead.
  34. ^ Krtička, J.; Kubát, J. (2010). "CMF Models of Hot Star Winds I. Test of the Sobolev Approximation in the case of Pure Line Transitions". arXiv:1005.0258v2 [astro-ph.SR].
  35. ^ "V* S Per – Semi-Regular Pulsating Star". SIMBAD. Retrieved 13 February 2013.
  36. ^ "V* RS Per – Semi-Regular Pulsating Star". SIMBAD. Retrieved 13 February 2013.
  37. ^ a b "V* SU Per – Semi-Regular Pulsating Star". SIMBAD. Retrieved 13 February 2013.
  38. ^ Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B.; Josselin, E.; Maeder, A.; Meynet, G. (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901.
  39. ^ a b "V* AX Per – Symbiotic Star". SIMBAD. Retrieved 15 February 2013.
  40. ^ a b Mikołajewska, J.; Kenyon, S. J. (1992). "On the Nature of the Symbiotic Binary AX Persei". 103 (2). Astronomical Journal: 579–592. Bibcode:1992AJ....103..579M. doi:10.1086/116085. {{cite journal}}: Cite journal requires |journal= (help)
  41. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/321369, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/321369 instead.
  42. ^ "V* DY Per – Semi-Regular Pulsating Star". SIMBAD. Retrieved 14 February 2013.
  43. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1051/0004-6361:200810349, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1051/0004-6361:200810349 instead.
  44. ^ Herbst, W.; Yau, A.; Semkov, E. (2010). "The Light Curve of V713 Per (HMW 15): Evidence for Gravitational Sculpting by an Object Embedded in the Circumstellar Disk". American Astronomical Society. 42: 335. Bibcode:2010AAS...21542931H.
  45. ^ "NGC 869 – Open (Galactic) Cluster". SIMBAD. Retrieved 17 July 2013.
  46. ^ "NGC 884 – Open (Galactic) Cluster". SIMBAD. Retrieved 17 July 2013.
  47. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/341865, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/341865 instead.
  48. ^ Levy, 2005, p. 86
  49. ^ a b Jones, K. G. (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge University Press. p. 139. ISBN 0-521-37079-5. {{cite book}}: |work= ignored (help)
  50. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/117865, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/117865 instead.
  51. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/376594, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/376594 instead.
  52. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/499808, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/499808 instead.
  53. ^ "Astronomers Discover Youngest and Lowest Mass Dwarfs in Solar Neighborhood". Science Daily. 24 April 2009. Retrieved 17 February 2013.
  54. ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1888/0333750888/5314, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1888/0333750888/5314 instead.
  55. ^ "NGC 1499 – HII (Ionized) region". SIMBAD. Retrieved 19 May 2013.
  56. ^ Barnard, E. E. (1895). "Photograph of the Nebula NGC 1499 Near the Star Ksi Persei". Astrophysical Journal. 2 (350): 350. Bibcode:1895ApJ.....2..350B. doi:10.1086/140157.
  57. ^ "NGC 1333 – Reflection Nebula". SIMBAD. Retrieved 19 May 2013.
  58. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/318060, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/318060 instead.
  59. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1086/510150, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1086/510150 instead.
  60. ^ "NASA/IPAC Extragalactic Database". Results for NGC 1260. Jet Propulsion Laboratory, California Institute of Technology. Retrieved 30 March 2013.
  61. ^ "NASA/IPAC Extragalactic Database". Results for NGC 1023. Jet Propulsion Laboratory, California Institute of Technology. Retrieved 30 March 2013.
  62. ^ "NGC 1023 – Interacting galaxies". SIMBAD. Retrieved 30 March 2013.
  63. ^ "NASA/IPAC Extragalactic Database". Results for Perseus+CLUSTER. Jet Propulsion Laboratory, California Institute of Technology. Retrieved 19 May 2013.
  64. ^ a b c Jennar, L.; Dunbar, B. (2008). "Interpreting the 'Song' of a Distant Black Hole". NASA. Retrieved 10 August 2013.
  65. ^ Kronk, G. W. "Observing the Perseids". Meteor Showers Online. Retrieved 2009-08-12.
  66. ^ Jenniskens, P. (2012). "Mapping Meteoroid Orbits: New Meteor Showers Discovered". Sky & Telescope: 22.

Cited texts

  • Levy, D. H. (2005). Deep Sky Objects. Prometheus Books. ISBN 1-59102-361-0.
  • Makemson, M. W. (1941). "The Morning Star Rises: An Account of Polynesian Astronomy". Yale University Press. {{cite journal}}: Cite journal requires |journal= (help)
  • Motz, L.; Nathanson, C. (1991). The Constellations: An Enthusiast's Guide to the Night Sky. Aurum Press. ISBN 978-1-85410-088-7.
  • Staal, J. D. W. (1988). The New Patterns in the Sky: Myths and Legends of the Stars. McDonald and Woodward. ISBN 978-0-939923-04-5.

Further reading

  • Ridpath, I.; Tirion, W. (2007). Stars and Planets Guide, Collins, London. ISBN 978-0-00-725120-9. Princeton University Press, Princeton. ISBN 978-0-691-13556-4.


Wikimedia Commons has media related to:
Perseus (constellation) (category)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Perseus_(constellation)&oldid=568580779"