Lyra: Difference between revisions
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In Lyra are the objects M56, M57, and Kuiper 90. [[Messier 56|M56]] is a rather loose [[globular cluster]] at a distance of approximately 32,900 [[light-year]]s, with a diameter of about 85 light years. Its apparent brightness is 8.3m. |
In Lyra are the objects M56, M57, and Kuiper 90. [[Messier 56|M56]] is a rather loose [[globular cluster]] at a distance of approximately 32,900 [[light-year]]s, with a diameter of about 85 light years. Its apparent brightness is 8.3m. |
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[[Ring Nebula|M57]], also known as the "Ring Nebula", 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 nebula]]e and the second to be discovered; its integrated magnitude is 8.8. Astronomers have determined that it is between 6,000 and 8,000 years old. 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 degrees [[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 (geometry)|cylinder]] seen from a slight angle.<ref name="objects">{{cite book |title = 300 Astronomical Objects: A Visual Reference to the Universe |first1 = Jamie |last1 = Wilkins |first2 = Robert |last2 = Dunn |publisher = Firefly Books |date = 2006 |location = Buffalo, New York |isbn = 978-1-55407-175-3}}</ref> |
[[Ring Nebula|M57]], also known as the "Ring Nebula" and NGC 6720,{{sfn|Levy|2005|p=123}} 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 nebula]]e and the second to be discovered; its integrated magnitude is 8.8.<ref name="objects"/> It was discovered in 1779 by [[Antoine Darquier]], 15 years after [[Charles Messier]] discovered the [[Dumbbell Nebula]].{{sfn|Levy|2005|p=125}} Astronomers have determined that it is between 6,000 and 8,000 years old;<ref name="objects"/> it is approximately one light-year in diameter.{{sfn|Levy|2005|p=124}} 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 degrees [[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 (geometry)|cylinder]] seen from a slight angle.<ref name="objects">{{cite book |title = 300 Astronomical Objects: A Visual Reference to the Universe |first1 = Jamie |last1 = Wilkins |first2 = Robert |last2 = Dunn |publisher = Firefly Books |date = 2006 |location = Buffalo, New York |isbn = 978-1-55407-175-3}}</ref> It can be found halfway between [[Gamma Lyrae]] and [[Beta Lyrae]].{{sfn|Levy|2005|p=124}} |
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[[Gliese 747AB|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.<ref name="a"/> |
[[Gliese 747AB|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.<ref name="a"/> |
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Revision as of 17:10, 17 July 2012
| Constellation | |
 | |
| Abbreviation | Lyr |
|---|---|
| Genitive | Lyrae |
| Pronunciation | /ˈlaɪərə/, genitive /ˈlaɪəriː/ |
| Symbolism | the Lyre, harp |
| Right ascension | 19 |
| Declination | +40 |
| Quadrant | NQ4 |
| Area | 286 sq. deg. (52nd) |
| Main stars | 5 |
| Bayer/Flamsteed stars | 25 |
| Stars with planets | 22 |
| Stars brighter than 3.00m | 1 |
| Stars within 10.00 pc (32.62 ly) | 3 |
| Brightest star | Vega (α Lyr) (0.03m) |
| 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 (/[invalid input: 'icon']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
Stars
Lyra's brightest stars include the following:[3]
- α Lyr (Vega). With an apparent brightness of 0.03m, this is the second 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.
Deep-sky objects
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,[4] 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.[5] It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula.[6] Astronomers have determined that it is between 6,000 and 8,000 years old;[5] it is approximately one light-year in diameter.[7] 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 degrees 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.[5] It can be found halfway between Gamma Lyrae and Beta Lyrae.[7]
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. [8]
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.[5]
Exoplanets
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.
History
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).[9]
Mythology
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].
Equivalents in other astronomical systems
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.[10]
Lyra was known as Urcuchillay by the Incas and was worshipped as an animal deity.[11][12]
Fictional references
In the poem Aniara by the Nobel laureate Harry Martinson, the space ship Aniara was travelling at high speed towards the stars of Lyra[13] 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 TV/Videogame series MegaMan 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.
Namesakes
USS Lyra (AK-101) was a United States Navy Crater class cargo ship named after the constellation.
Citations
select an article title from: Wikisource:1911 Encyclopædia Britannica
- ^ 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.
- ^ Lesley Brown: The New Shorter Oxford English Dictionary. Vol. 1: A−M. Clarendon Press, Oxford 1993, p. 1651
- ^ a b c Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
- ^ Levy 2005, p. 123.
- ^ 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.
- ^ Levy 2005, p. 125.
- ^ a b Levy 2005, p. 124.
- ^ Christopher Watson, Christopher, Watson. "VSX : Detail for VSX J185422.2+365107". Aavso.org. Retrieved 2012-05-16.
{{cite web}}: CS1 maint: multiple names: authors list (link) - ^ "Star Tales - Lyra". Ian Ridpath's Star Tales. Retrieved 2007-10-17.
- ^ "World_Archaeological_Congress.pdf" (PDF). The Astronomy of the Boorong. Retrieved 2007-10-17. [dead link]
- ^ Allen, Richard Hinckley (2003-03) [1936]. Star Names and Their Meanings. Kessenger Publishing. p. 532. ISBN 978-0-7661-4028-8. Retrieved 2008-03-22.
{{cite book}}: Check date values in:|date=(help) - ^ 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.
- ^ Aniara, p10
