Lyra

From Wikipedia, the free encyclopedia
  (Redirected from Lyra (constellation))
Jump to: navigation, search
For other uses, see Lyra (disambiguation).
Lyra
Constellation
Lyra
Abbreviation Lyr
Genitive Lyrae
Pronunciation /ˈlaɪərə/, genitive /ˈlaɪər/
Symbolism Lyre, harp
Right ascension 19
Declination +40
Family Hercules
Quadrant NQ4
Area 286 sq. deg. (52nd)
Main stars 5
Bayer/Flamsteed
stars
25
Stars with planets 62
Stars brighter than 3.00m 1
Stars within 10.00 pc (32.62 ly) 3
Brightest star Vega (α Lyr) (0.03m)
Nearest star 2MASS J18353790+3259545
(18.51 ly, 5.67 pc)
Messier objects 2
Meteor showers Lyrids
June Lyrids
Alpha Lyrids
Bordering
constellations
Draco
Hercules
Vulpecula
Cygnus
Visible at latitudes between +90° and −40°.
Best visible at 21:00 (9 p.m.) during the month of August.
[1]

Lyra (/ˈlaɪərə/; Latin for lyre, from Greek λύρα)[2] is a small constellation. It is one of 48 listed by the 2nd century astronomer Ptolemy, and is one of the 88 constellations recognized by the International Astronomical Union. Its principal star, Vega (Abhijit in Sanskrit), a corner of the Summer Triangle, is one of the brightest stars in the sky. Beginning at the north, Lyra is bordered by Draco, Hercules, Vulpecula, and Cygnus.[3]

Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months.[citation needed]

Notable features[edit]

The constellation Lyra as it can be seen by the naked eye.

Stars[edit]

Lyra's brightest stars include the following:[3]

  • α Lyr (Vega). With an apparent brightness of 0.03m, it is the third brightest star of the northern hemisphere (after Arcturus) and the fifth brightest star in all; its spectral class is A0 V and it lies at a distance of only 25.3 ly.
  • β Lyr (Sheliak). A group of eclipsing binaries is named after this variable star (3.45m, spectral class B8 II), the Beta-Lyrae-stars.
  • γ Lyr (Sulafat). The main star of this multiple star system is of magnitude 3.24m and spectral class B9 III.
  • δ1 Lyr. A double star consisting of a blue-white star of mag. 6m and a semi-regular red giant.
  • ε Lyr. A well-known quadruple star, also called "the Double Double" because each of the two brighter components is a double star.
  • ζ Lyr. Another double star, which can be split using binoculars.
  • RR Lyr lends its name to a class of pulsating variable, RR Lyrae-stars.
  • DM Lyr is a dwarf nova, namely a close binary consisting of a white dwarf and a low mass star where the former strips off material from the latter, forming an accretion disc which explodes brightly from time to time.
  • Kepler-37 - star with smallest extrasolar planet known so far (February 2013)
  • Kepler-62 - star with a five-planet system discovered by Kepler spacecraft in April 2013.

Deep-sky objects[edit]

Messier 56 is composed of a large number of stars, tightly bound to each other by gravity.[4] In Lyra are the objects M56, M57, and Kuiper 90. M56 is a rather loose globular cluster at a distance of approximately 32,900 light-years, with a diameter of about 85 light years. Its apparent brightness is 8.3m.

M57, also known as the "Ring Nebula" and NGC 6720,[5] has a diameter of one light-year and is at a distance of 2,000 light-years from Earth. It is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8.[6] It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula.[7] Astronomers have determined that it is between 6,000 and 8,000 years old;[6] it is approximately one light-year in diameter.[8] The outer part of the nebula appears red in photographs because of emission from ionized hydrogen. The middle region is colored green; doubly-ionized oxygen emits greenish-blue light. The hottest region, closest to the central star, appears blue because of emission from helium. The central star itself is a white dwarf with a temperature of 120,000 Kelvin. In telescopes, the nebula appears as a visible ring with a green tinge; it is slightly elliptical because its three-dimensional shape is a torus or cylinder seen from a slight angle.[6] It can be found halfway between Gamma Lyrae and Beta Lyrae.[8]

Kuiper 90 is also known as 17 Lyrae C (Gliese 747AB), a red dwarf system near 17 Lyrae, but 26 light years from the Sun. Its period is 5 years, and its magnitude is 11.26 in the V band.[3]

BD +36 3317 [1], a white star in the young open cluster Stephenson 1, was discovered as a binary eclipsing system by Violat-Bordonau in 2008; its period is 4.30216 days; its other name is VSX J185422.2+365107.[9]

NGC 6745 is an irregular spiral galaxy in Lyra that is at a distance of 208 million light-years. Several million years ago, it collided with a smaller galaxy, which created a region filled with young, hot, blue stars. Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably elliptical galaxy.[6]

The Hercules–Corona Borealis Great Wall is a giant galaxy filament situated 10 billion light years away. With the size nearly equal to its distance; 10 billion light years in length, it is the largest known structure in the universe, covering the entirety of Lyra.

Exoplanets[edit]

An image showing Lyra

Exoplanets including WASP-3b, HAT-P-5b, GJ 758 b and c, HD 178911 Bb, HD 177830 b, TrES-1, and HD 173416 b have been discovered in Lyra. In January 2010 the Kepler Mission announced the discovery of the additional planets Kepler-7b, Kepler-8b, and three planets around Kepler-9 are expected to be the first of many discovered by the mission, which has a significant part of its field of view in Lyra.

In April 2013, it was announced that of the five planets orbiting Kepler-62, at least two -- Kepler-62e and Kepler-62f—are within the boundaries of the habitable zone of that star, where scientists think liquid water could exist, and are both candidates for being a solid, rocky, earth-like planet. The exoplanets are 1.6 and 1.4 times the diameter of Earth respectively, with their star Kepler-62 at a distance of 1,200 light-years.[10]

History[edit]

In the past, Lyra was often represented on star maps as a vulture or an eagle carrying a lyre, either enclosed in its wings, or in its beak. It was sometimes referred to as Aquila Cadens or Vultur Cadens (falling eagle or falling vulture).[11] This historical association is preserved in the name of its brightest star, Vega, which is derived from an Arabic term meaning "swooping eagle."[12]

Mythology[edit]

Lyra can be seen on the right of this c. 1825 star map from Urania's Mirror.

In Greek mythology, Lyra was associated with the myth of Orpheus, the musician who was killed by the Bacchantes. After his death, his lyre was thrown into the river; Zeus sent an eagle to retrieve the lyre, and ordered both of them to be placed in the sky.[citation needed] In Wales, Lyra is known as King Arthur's Harp (Talyn Arthur), and King David's harp [2]. The Persian Hafiz called it the Lyre of Zurah.[3] It has been called the Manger of the Infant Saviour, Praesepe Salvatoris [4].

In Japanese mythology, originating from the Chinese Qixi festival, Vega is sometimes called Tanabata (or Orihime), a celestial princess or goddess. She falls in love with a mortal, Kengyu (or Hikoboshi), represented by the star Altair. But when Tanabata’s father finds out, he is enraged and forbids her to see this mere mortal. Thus the two lovers are placed in the sky, where they are separated by the Celestial River, known to us as Milky Way. Yet the sky gods are kind. Each year, on the 7th night of the 7th moon, a bridge of magpies forms across the Celestial River, and the two lovers are reunited. Sometimes Kengyu’s annual trip across the Celestial River is treacherous, though, and he doesn’t make it. In that case, Tanabata’s tears form raindrops that fall over Japan.

Many Japanese celebrations of Tanabata are held in July, but sometimes they are held in August. If it rains, the raindrops are thought to be Tanabata’s tears because Kengyu could not meet her. Sometimes the meteors of the Perseid shower are said to be Tanabata’s tears. [13]

Equivalents in other astronomical systems[edit]

Vega and its surrounding stars are also treated as a constellation in other cultures.

In Australian Aboriginal astronomy, Lyra is known by the Boorong people in Victoria as the Malleefowl constellation.[14]

Lyra was known as Urcuchillay by the Incas and was worshipped as an animal deity.[15][16]

In History[edit]

  • John Adams left a family tradition that Lyra was intended to be the "new constellation" of the thirteen stars in the original flag of the United States.[17]

In popular culture[edit]

See also: Vega in fiction
  • In the book series His Dark Materials by Philip Pullman, Lyra Belacqua is the protagonist of all three books. Science and astronomy feature prominently in this dystopian adventure saga.
  • In the poem Aniara by the Nobel laureate Harry Martinson, the space ship Aniara was travelling at high speed towards the stars of Lyra[18] after having been shipwrecked by collisions with asteroids.
  • In the film K-PAX, the constellation of Lyra is the location of the planet K-PAX, an inhabited world that orbits twin stars and has seven moons.
  • In the film Contact, the message intercepted by Jodi Foster's character is coming from Vega, the brightest star in the Lyra constellation.
  • In the T.V. and video game series Mega Man Star Force, Lyra is the alien that accompanies Sonia Sky, who is otherwise known as Sonia Strumm in the game series, but Lyra is sometimes known as Harp, most commonly found in the original Japanese version, Ryuusei no Rockman.
  • In the anime Fairy Tail, Lyra is a silver key that belongs to Lucy Heartfilia, a celestial spirit mage. Lyra's ability is to portray emotion through singing.
  • In the TV show My Little Pony: Friendship Is Magic, there is a background character who fans have named Lyra.
  • In the Watty Winner for Fantasy - On The Rise 2012 on Wattpad.com,[19] The Lores of Lyra - Rising Star Lyra is the watcher over earth and its inhabitants.

Namesakes[edit]

USS Lyra (AK-101) was a United States Navy Crater-class cargo ship named after the constellation.

Citations[edit]

  1. ^ Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0-00-725120-9. Princeton University Press, Princeton. ISBN 978-0-691-13556-4.
  2. ^ Lesley Brown: The New Shorter Oxford English Dictionary. Vol. 1: A−M. Clarendon Press, Oxford 1993, p. 1651
  3. ^ a b c Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
  4. ^ "A Collection of Ancient Stars". ESA/Hubble Picture of the Week. Retrieved 20 August 2012. 
  5. ^ Levy 2005, p. 123.
  6. ^ a b c d Wilkins, Jamie; Dunn, Robert (2006). 300 Astronomical Objects: A Visual Reference to the Universe. Buffalo, New York: Firefly Books. ISBN 978-1-55407-175-3. 
  7. ^ Levy 2005, p. 125.
  8. ^ a b Levy 2005, p. 124.
  9. ^ Christopher Watson, Christopher, Watson. "VSX : Detail for VSX J185422.2+365107". Aavso.org. Retrieved 2012-05-16. 
  10. ^ Grant, Andrew (18 April 2013). "Most Earthlike planets yet seen bring Kepler closer to its holy grail". ScienceNews.org. Retrieved 19 April 2013. 
  11. ^ "Star Tales - Lyra". Ian Ridpath's Star Tales. Retrieved 2007-10-17. 
  12. ^ Ian Ridpath (2002) Stars and Planets, p. 108 [ISBN 0-7894-8988-0].
  13. ^ "Vega is the harp star". Earthsky Communications Inc. Retrieved 12 October 2013. 
  14. ^ "World_Archaeological_Congress.pdf". The Astronomy of the Boorong. Retrieved 2007-10-17. [dead link]
  15. ^ Allen, Richard Hinckley (March 2003) [1936]. Star Names and Their Meanings. Kessenger Publishing. p. 532. ISBN 978-0-7661-4028-8. Retrieved 2008-03-22. 
  16. ^ D'Altroy, Terence N. (2002). "The Inca Pantheon". The Incas. The Peoples of America. Oxford: Blackwell Publishing. p. 149. ISBN 978-0-631-17677-0. 
  17. ^ "The Evolution of the Stars and Stripes" in State Service magazine, June 1919, page 61|http://books.google.com/books?id=hw0UAAAAIAAJ&pg=RA4-PA61&lpg=RA4-PA61&dq=lyra+13+star+flag&source=bl&ots=IP5RaZyv9G&sig=yb--iEcHSLKCdHpFxNXl5sGaijk&hl=en&sa=X&ei=OOqGUrbmHcjm2gWSvIGQAw&ved=0CEYQ6AEwCQ#v=onepage&q=lyra%2013%20star%20flag&f=false
  18. ^ Aniara. p. 10. 
  19. ^ http://www.wattpad.com/story/1091660

Coordinates: Sky map 19h 00m 00s, +40° 00′ 00″