Canes Venatici

Canes Venatici

Constellation
List of stars in Canes Venatici
Abbreviation	CVn
Genitive	Canum Venaticorum
Pronunciation	/ˈkeɪniːz vɨˈnætɨsaɪ/ Cánes Venátici, genitive /ˈkeɪnəm vɨnætɨˈkɒrəm/
Symbolism	the Hunting Dogs
Right ascension	13 h
Declination	+40°
Quadrant	NQ3
Area	465 sq. deg. (38th)
Main stars	2
Bayer/Flamsteed stars	21
Stars with planets	4
Stars brighter than 3.00m	1
Stars within 10.00 pc (32.62 ly)	2
Brightest star	Cor Caroli (α CVn) (2.90m)
Nearest star	DG CVn (25.89 ly, 7.94 pc)
Messier objects	5
Meteor showers	Canes Venaticids
Bordering constellations	Ursa Major Boötes Coma Berenices
Visible at latitudes between +90° and −40°. Best visible at 21:00 (9 p.m.) during the month of May.

Canes Venatici /ˈkeɪniːz vɨˈnætɨsaɪ/ is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for "hunting dogs", and the constellation is often depicted in illustrations as representing the dogs of Boötes the Herdsman, a neighboring constellation.

History

The stars of Canes Venatici are not bright. In classical times, they were included by Ptolemy within the constellation Ursa Major in his star catalogue. α CVn was Ptolemy's "28th of Ursa Major", and β CVn was his "29th of Ursa Major".^{[citation needed]}

In the medieval times, the identification of these stars with the dogs of Boötes arose through a mistranslation. Some of Boötes' stars were traditionally described as representing the club (Greek, Κολλοροβος) of Boötes. When the Greek astronomer Ptolemy's Almagest was translated from Greek to Arabic, the translator Johannitius (following Alberuni) did not know the Greek word and rendered it as the nearest-looking Arabic word, writing العصى ذات الكلاب in ordinary unvowelled Arabic text "al-`aşā dhāt al-kullāb", which means "the spearshaft having a hook". When the Arabic text was translated into Latin, the translator Gerard of Cremona (probably in Spain) mistook the Arabic word كلاب for kilāb (the plural of كلب kalb), meaning "dogs", writing hastile habens canes ("spearshaft having dogs").^{[1][2]
[3]
[4]} In 1533, the German astronomer Peter Apian depicted Boötes as having two dogs with him.^[5][6]

Canes Venatici depicted in Hevelius' star atlas.

These spurious dogs floated about the astronomical literature until Hevelius decided to specify their presence in the sky by making them a separate constellation in 1687.^[7][8] Hevelius chose the name Asterion (from the Greek 'αστέριον, meaning the "little star",^[9] the diminutive of 'αστηρ the "star", or adjective meaning "starry"^[10]) for the northern dog and Chara (from the Greek χαρά, meaning "joy") for the southern dog, as Canes Venatici, the Hunting Dogs, in his star atlas.^[8][11] In his star catalogue, the Czech astronomer Becvar assigned Asterion to β CVn and Chara to α CVn.^[12]

Notable features

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

Stars

Canes Venatici contains no bright stars, α and β CVn being only of 3rd and 4th magnitude respectively.

• α CVn (Asterion, Cor Caroli) is the constellation's brightest star, named by Sir Charles Scarborough in memory of King Charles I, the deposed king of Britain.^[8][13] Legend has it that α CVn was brighter than usual during the Restoration, as Charles II returned to England to take the throne. Cor Caroli is a wide double star, with a primary of magnitude 2.9 and a secondary of magnitude 5.6; the primary is 110 light-years from Earth. The primary also has an unusually strong variable magnetic field.^[8]

• β CVn (Chara) is a yellow-hued main sequence star of magnitude 4.2, 27 light-years from Earth. Its common name comes from the word for "joy".^[8]

• Y CVn (La Superba) is a semiregular variable star that varies between magnitudes 5.0 and 6.5 over a period of around 158 days. It is a carbon star and is famous for being deep red.^[8]

• AM CVn, a very blue star of magnitude 14, is the prototype of a special class of cataclysmic variable stars, in which the companion star is a white dwarf, rather than a main sequence star.

• RS CVn is the prototype of a special class of binary stars^[14] of chromospherically active and optically variable components.

Deep-sky objects

Messier 51, the Whirlpool Galaxy taken by the Hubble Space Telescope.

Canes Venatici contains five Messier objects, including four galaxies. One of the more significant galaxies in Canes Venatici is the Whirlpool Galaxy (M51, NGC 5194) and NGC 5195, a small barred spiral galaxy that is seen face on. This was the first galaxy recognised as having a spiral structure, this structure being first observed by Lord Rosse in 1845.^[8] It is a face-on spiral galaxy 37 million light-years from Earth. Widely considered to be one of the most beautiful galaxies visible, M51 has many star-forming regions and nebulae in its arms, coloring them pink and blue in contrast to the older yellow core. M51 has a smaller companion, NGC 5195, that has very few star-forming regions and thus appears yellow. It is passing behind M51 and may be the cause of the larger galaxy's prodigious star formation.^[15]

NGC 4631 taken by the Hubble Space Telescope.

Other notable spiral galaxies in Canes Venatici are the Sunflower Galaxy (M63, NGC 5055), M94 (NGC 4736), and M106 (NGC 4258). M63, the Sunflower Galaxy, was named for its appearance in large amateur telescopes. It is a spiral galaxy with an integrated magnitude of 9.0. M94 is a small face-on spiral galaxy with an approximate magnitude of 8.0, about 15 million light-years from Earth.^[8] NGC 4631 is a barred spiral galaxy, which is one of the largest and brightest edge-on galaxies in the sky.^[16]

M3 (NGC 5272) is a globular cluster 32,000 light-years from Earth. It is 18' in diameter, and at magnitude 6.3 is bright enough to be seen with binoculars. It can even be seen with the naked eye under particularly dark skies.^[8]

M94, also classified as NGC 4736, is a face-on spiral galaxy 15 million light-years from Earth. It has very tight spiral arms and a bright core. The outskirts of the galaxy are incredibly luminous in the ultraviolet because of a ring of new stars surrounding the core, 7,000 light-years in diameter. Though astronomers are not sure what has caused this ring of new stars, some hypothesize that it is from shock waves caused by a bar that is thus far invisible.^[15]

References

Citations

References

• Allen, Richard Hinckley (1899), Star Names: Their Lore and Meaning 
• Apianus, Petrus (1533), Horoscopion generale 
• Bečvář, Antonín (1951), Atlas Coeli II - Catalogue 1950.0, Czechoslovak Astronomical Society 
• Hevelius, Johannes (1690), Firmamentum Soviescianum 
• Kunitzsch, P. (1959), Arabische Sternnamen in Europa, Otto Harassowitz 
• Kunitzsch, P. (1974), Der Almagest: Die Syntaxis Mathematica des Claudius Ptolemäus in arabisch-lateinischer Ūberlieferung, Otto Harassowitz 
• Kunitzsch, P. (1990), Der Sternkatalog des Almagest Die arabisch-mittelalterliche Tradition: II Die lateinische Ūbersetzung Gerhards von Cremona, Otto Harassowitz 
• Kunitzsch, P.; Smart, T. (2006), A Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations (2nd Revised ed.), Sky Publishing, ISBN 1-931559-44-9 
• Ridpath, Ian (2001), Wil Tirion (3rd ed.), Princeton University Press, ISBN 0-691-08913-2  Missing or empty |title= (help)
• Ridpath, Ian (2007), Wil Tirion (4th ed.), Princeton University Press, ISBN 978-0-691-13556-4  Missing or empty |title= (help)
• Wilkins, Jamie; Dunn, Robert (2006), 300 Astronomical Objects: A Visual Reference to the Universe, Firefly Books, ISBN 9781554071753 

External links

Wikimedia Commons has media related to Canes Venatici.

• Photographic Catalogue of Deep Sky Objects in Canes Venatici
• The Deep Photographic Guide to the Constellations: Canes Venatici
• Star Tales – Canes Venatici, by Ian Ridpath
• Canes Venatici at Constellation Guide

Coordinates: 13^h 00^m 00^s, +40° 00′ 00″