Draco (constellation)

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Draco
Constellation
Draco
AbbreviationDra
GenitiveDraconis
Pronunciation
Symbolismthe
8th)
Main stars17
Bayer/Flamsteed
stars
76
Stars with planets19
Stars brighter than 3.00m3
Stars within 10.00 pc (32.62 ly)7
Brightest starγ Dra (Eltanin) (2.24m)
Messier objects1
Meteor showersDraconids
Bordering
constellations
Visible at latitudes between +90° and −15°.
Best visible at 21:00 (9 p.m.) during the month of July.

Draco is a

modern constellations today. The north pole of the ecliptic is in Draco.[1] Draco is circumpolar
from northern latitudes, meaning that it never sets and can be seen at any time of year.

Features

The constellation Draco as it can be seen by the naked eye

Stars

precession, it will again be the pole star around the year AD 21000. It is a blue-white giant star of magnitude 3.7, 309 light-years from Earth. The traditional name of Alpha Draconis, Thuban, means "head of the serpent".[1]

There are three stars above magnitude 3 in Draco. The brighter of the three, and the brightest star in Draco, is

aberration of starlight was discovered in 1728 when James Bradley observed Gamma Draconis. Nearby Beta Draconis, traditionally called Rastaban, is a yellow giant star of magnitude 2.8, 362 light-years from Earth. Its name shares a meaning with Thuban, "head of the serpent".[1]
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).

Draco is home to several double stars and binary stars.

arcseconds.[4] Mu Draconis, traditionally called Alrakis, is a binary star with two white components. Magnitude 5.6 and 5.7, the two components orbit each other every 670 years. The Alrakis system is 88 light-years from Earth. Nu Draconis is a similar binary star with two white components, 100 light-years from Earth. Both components are of magnitude 4.9 and can be distinguished in a small amateur telescope or a pair of binoculars. Omicron Draconis is a double star divisible in small telescopes. The primary is an orange giant of magnitude 4.6, 322 light-years from Earth. The secondary is of magnitude 7.8. Psi Draconis (the proper name is Dziban[3]) is a binary star divisible in binoculars and small amateur telescopes, 72 light-years from Earth. The primary is a yellow-white star of magnitude 4.6 and the secondary is a yellow star of magnitude 5.8. 16 Draconis and 17 Draconis are part of a triple star 400 light-years from Earth, divisible in medium-sized amateur telescopes. The primary, a blue-white star of magnitude 5.1, is itself a binary with components of magnitude 5.4 and 6.5. The secondary is of magnitude 5.5 and the system is 400 light-years away.[1] 20 Draconis is a binary star with a white-hued primary of magnitude 7.1 and a yellow-hued secondary of magnitude 7.3 located east-northeast of the primary. The two are separated by 1.2 arcseconds at their maximum and have an orbital period of 420 years. As of 2012, the two components are approaching their maximum separation.[4] 39 Draconis is a triple star 188 light-years from Earth, divisible in small amateur telescopes. The primary is a blue star of magnitude 5.0, the secondary is a yellow star of magnitude 7.4, and the tertiary is a star of magnitude 8.0; the tertiary appears to be a close companion to the primary. 40 Draconis and 41 Draconis are a binary star divisible in small telescopes. The two orange dwarf stars are 170 light-years from Earth and are of magnitude 5.7 and 6.1.[1]

R Draconis is a red Mira-type variable star with a period of about 8 months. Its average minimum magnitude is approximately 12.4, and its average maximum magnitude is approximately 7.6. It was discovered to be a variable star by Hans Geelmuyden in 1876.[5]

The constellation contains the star recently named Kepler-10, which has been confirmed to be orbited by Kepler-10b.

Deep-sky objects

One of the

north ecliptic pole to the west-northwest. It is also related to IC 4677, a nebula that appears as a bar 1.8 arcminutes to the west of the Cat's Eye nebula. In long-term exposures, IC 4677 appears as a portion of a ring surrounding the planetary nebula.[4]

There are several faint

light years, discovered by Albert G. Wilson of Lowell Observatory in 1954.[8] Another dwarf galaxy found in this constellation is PGC 39058.

PGC 39058
, a dwarf galaxy found within the Draco constellation – picture taken by ESA/Hubble & NASA.

Draco also features several

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.[6]

Q1634+706 is a quasar that holds the distinction of being the most distant object usually visible in an amateur telescope. At magnitude 14.4, it appears star-like, though it is at a distance of 12.9 billion light-years. The light of Q1634+706 has taken 8.6 billion years to reach Earth, a discrepancy attributable to the expansion of the universe.[4]

The Hercules–Corona Borealis Great Wall, possibly the largest known structure in the universe, covers a part of the southern region of Draco.

Mythology

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

Draco (also known as

romanized: Ophis, lit.'serpent')[9] is one of the 48 constellations listed in Ptolemy's Almagest (2nd century), adopted from the list by Eudoxus of Cnidus (4th century BC).[10]

Draco was identified with several different

The

Traditional Arabic astronomy does not depict a dragon in modern-day Draco, which is called the Mother Camels. Instead, two hyenas, represented by Eta Draconis and Zeta Draconis are seen attacking a baby camel (a dim star near Beta Draconis), which is protected by four female camels, represented by Beta Draconis, Gamma Draconis, Nu Draconis, and Xi Draconis. The nomads who own the camels are camped nearby, represented by a cooking tripod composed of Upsilon, Tau, and Sigma Draconis.[17] However Arabic astronomers also knew of the Greek interpretation of the constellation, referring to it in Arabic as At-Tinnin (التنين, 'the dragon'), which is the source of the formal name of Gamma Draconis, Eltanin, from raʾs al-tinnīn ('the head of the dragon').[18]

Meteor showers

The October

21P/Giacobini-Zinner. The shower peaks on 8 October and it has experienced storms in 1933 and 1946, when the zenithal hourly rate (ZHR) was up to 10,000 meteors per hour.[19] Further outbursts were observed in 1985, 1998,[19] and 2011. During the 2011 outburst, ZHR reached 400 meteors/hour, however it was largely unnoticed visually due to interference by the bright Moon.[20]

The

Namesakes

Crater class cargo ship named after the constellation.[citation needed
]

The main character in the 1996 film Dragonheart gets his name from this constellation. The film also reveals that Draco is actually a dragon heaven, where dragons go when their time in this world is complete, if they have upheld the oath of an ancient dragon to guard mankind, with dragons otherwise fading into nothing upon their deaths. At the conclusion of the film, Draco, the last dragon, ascends into the constellation after he sacrifices himself to destroy an evil king.[citation needed]

The

Fyodor Dus-Chotimirsky.[22]

Draco Malfoy, an antagonist in the Harry Potter series, is named after the constellation as well.[23]

See also

References

Citations

  1. ^ a b c d e f Ridpath & Tirion 2001, pp. 142–143.
  2. ^ Staal 1988, pp. 239–240.
  3. ^ a b "Naming Stars". IAU.org. Retrieved 30 July 2018.
  4. ^ a b c d e French, Sue (July 2012). "By Draco's Scaly Folds". Sky & Telescope. 124 (1): 56. .
  5. ^ MacRobert, Alan (July 2012). "The Rise of R Draconis". Sky & Telescope. 124 (1).
  6. ^ a b Wilkins & Dunn 2006.
  7. ^ Frommert, Hartmut (October 2018) [May 1995]. "Messier 102. An article on the controversy". messier.seds.org. Retrieved 2 August 2020.
  8. ^ Boutsikas 2011, p. 307.
  9. ^ Thomas L. Heath, Greek Astronomy (1932), p. 118.
  10. ^ Hyginus De Astron. 2.3
  11. ^ a b c Staal 1988, p. 237.
  12. ^ Aelius Aristides, Panathenaicus 13.189.4–5
  13. ^ a b Boutsikas 2011, pp. 307–308.
  14. ^ Boutsikas 2011, p. 308 n. 14.
  15. ^ Ian Ridpath. "Star Tales – Draco". Retrieved 16 February 2022.
  16. ^ Staal 1988, p. 239.
  17. ^ Kunitzsch, P., “[1]”, in: Encyclopaedia of Islam, Second Edition (2012)
  18. ^ .
  19. .
  20. ^ Jenniskens, Peter (September 2012). "Mapping Meteoroid Orbits: New Meteor Showers Discovered". Sky & Telescope: 24.
  21. .
  22. ^ "The Harry Potter characters named after constellations". Pottermore.

References

External links