Draco (constellation): Difference between revisions

Draco
Constellation
	List of stars in Draco
Abbreviation	Dra
Genitive	Draconis
Pronunciation	/ˈdreɪkoʊ/, genitive /drəˈkoʊnɨs/
Symbolism	the Dragon
Right ascension	17
Declination	+65
Quadrant	NQ3
Area	1083 sq. deg. (8th)
Main stars	14
Bayer/Flamsteed; stars	76
Stars with planets	13
Stars brighter than 3.00m	3
Stars within 10.00 pc (32.62 ly)	7
Brightest star	γ Dra (Eltanin) (2.24m)
Messier objects	1
Meteor showers	Draconids
Bordering; constellations	Boötes; Hercules; Lyra; Cygnus; Cepheus; Ursa Minor; Camelopardalis; Ursa Major
	Visible at latitudes between +90° and −15°.; Best visible at 21:00 (9 p.m.) during the month of July.

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Revision as of 15:15, 9 May 2012

Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar (that is, never setting) for many observers in the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations today.

Notable features

Stars

Eltanin (Gamma Draconis) is the brightest star in Draco, with an apparent magnitude of 2.24.

The constellation contains the star recently named Kepler-10 which has been confirmed to be orbited by Kepler-10b, the smallest ever rocky Earth-sized planet detected outside of our solar system.

The star Thuban (α Draconis) was the northern pole star around 2700 BC, during the time of the ancient Egyptians. Due to the effects of precession, it will once again be the pole star around the year 21000 AD.

Deep-sky objects

One of the deep-sky objects in Draco is the Cat's Eye Nebula (NGC 6543), a planetary nebula approximately 3,000 light-years away that was discovered by English astronomer William Herschel in 1786. It has a very complex shape due to gravitational interactions between the components of the multiple star at its center, the progenitor of the nebula approximately 1,000 years ago.^[1]

There are several faint galaxies in Draco, one of which is the lenticular galaxy NGC 5866, sometimes considered to be Messier Object 102. Another is the Draco Dwarf Galaxy, one of the least luminous galaxies with an absolute magnitude of -8.6 and a diameter of only about 3,500 light years, discovered by Albert G. Wilson of Lowell Observatory in 1954. Another dwarf galaxy found in this constellation is PGC 39058.

Draco also features several interacting galaxies and galaxy clusters. One such massive cluster is Abell 2218, located at a distance of 3 billion light-years (redshift 0.171). It acts as a gravitational lens for even more distant background galaxies, allowing astronomers to study those galaxies as well as Abell 2218 itself; more specifically, the lensing effect allows astronomers to confirm the cluster's mass as determined by x-ray emissions. One of the most well-known interacting galaxies is Arp 188, also called the "Tadpole Galaxy". Named for its appearance, which features a "tail" of stars 280,000 light-years long, the Tadpole Galaxy is at a distance of 420 million light-years (redshift 0.0314). The tail of stars drawn off the Tadpole Galaxy appears blue because the gravitational interaction disturbed clouds of gas and sparked star formation.^[1]

Mythology

File:Dracourania.jpg

Draco coils around the north celestial pole, as depicted in Urania's Mirror, a set of constellation cards published in London c.1825

Dragons in Greek mythology that may have inspired^{[citation needed]} the constellation's name include Ladon, the dragon who guarded the golden apples of the Hesperides; the dragon killed by Cadmus before founding the city of Thebes, Greece; and the dragon that guarded the Golden Fleece and was killed by Jason. (see Argonautica)

In Roman legend, Draco was a dragon killed by the goddess Minerva and tossed into the sky upon his defeat.{{Citation needed|date=December 2008 JIIIJP

Religion

Early Christians^{[citation needed]} saw Draco as the serpent who tempted Adam and Eve in the Garden of Eden. (See Book of Genesis chapter 3)

Equivalents

The Arabs did not interpret the constellation as a dragon, seeing instead an asterism called the Mother Camels.^{[citation needed]}

In Chinese astronomy, the stars of Draco are located in two areas: the Purple Forbidden enclosure (紫微垣, Zǐ Wēi Yuán) and the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ). A region at the curve of the Dragon's tail is called "Tien Choo" or "Heaven's Kitchen".^{[citation needed]}

Namesakes

USS Draco (AK-79) was a United States Navy Crater class cargo ship named after the constellation. The main character in the 1996 film Dragonheart gets his name from this constellation. The chess opening called the Dragon Variation of the Sicilian Defense was also named after the constellation by Russian chess master Fyodor Dus-Chotimirsky.J.K. Rowling also named the character Draco Malfoy after the constellation in her Harry Potter book series.

References

^ ^a ^b Wilkins, Jamie; Dunn, Robert (2006). 300 Astronomical Objects: A Visual Reference to the Universe (1st ed.). Buffalo, New York: Firefly Books. ISBN 978-1-55407-175-3. {{cite book}}: |access-date= requires |url= (help)

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.
موسوعة اسماء النجوم عند العرب في الفلك القديم والحديث - د. عبد الرحيم بدر - 1998

External links

The Deep Photographic Guide to the Constellations: Draco
Star Tales – Draco myj dfui asgi dvnasuiodgxfcui aw9s0er789dxufc80ds=0x
[http://www.starryskies.com/The_sky/constellations/draco.html

[objects-1] Wilkins, Jamie; Dunn, Robert (2006). 300 Astronomical Objects: A Visual Reference to the Universe (1st ed.). Buffalo, New York: Firefly Books. ISBN 978-1-55407-175-3. {{cite book}}: |access-date= requires |url= (help)

[1]

@@ Line 52: / Line 52: @@
 Dragons in Greek mythology that may have inspired{{Citation needed|date=January 2012}} the constellation's name include [[Dragons in Greek mythology|Ladon]], the dragon who guarded the golden apples of the [[Hesperides#The Garden of the Hesperides|Hesperides]]; the [[dragon]] killed by [[Cadmus]] before founding the city of [[Thebes, Greece]]; and the dragon that guarded the [[Golden Fleece]] and was killed by [[Jason]]. (see [[Argonautica]])
-In Roman legend, Draco was a dragon killed by the goddess [[Minerva]] and tossed into the sky upon his defeat.{{Citation needed|date=December 2008}}
+In Roman legend, Draco was a dragon killed by the goddess [[Minerva]] and tossed into the sky upon his defeat.{{Citation needed|date=December 2008 JIIIJP
 ===Religion===