Ursa Minor

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Ursa minor
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Abbreviation	UMi
Genitive	Ursae Minoris
Symbology	the Small Bear
Right ascension	15 h
Declination	70°
Area	List of constellations by area>Ranked 56th
Number of stars (magnitude < 3)	2
Brightest star	Polaris (Apparent magnitude>App. magnitude 2.02)
Meteor showers	Ursids
Bordering constellations	Draco Camelopardalis Cepheus
Visible at latitudes between +90° and −10° Best visible at 21:00 (9 p.m.) during the month of June
Ursa Minor is a constellation in the northern sky, the name of which means Small Bear in Latin. It is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy. It is notable as the location of the north celestial pole, although this will change after some centuries due to the precession of the equinoxes. Contents 1 Notable features 2 Notable 3 History 4 Mythology 5 Notable and named stars 6 See also 7 External links Notable features Ursa Minor contains an asterism colloquially known as the Little Dipper because its seven brightest stars seem to form a ladle, or dipper shape. The star at the end of the dipper handle is Polaris, the North Star. Polaris can also be found by following a line through the two stars which form the end of the "bowl" of the Big Dipper, a nearby asterism found in the constellation Ursa Major. The two brightest stars are: Polaris (α UMi): a yellow supergiant of spectral type F7 and an apparent brightness of 2.02m β UMi (Kochab): a giant orange star; spectral type K4; brightness 2.08 Notable Ursa Minor Dwarf, a dwarf galaxy. History This constellation is said to have been introduced in the 6th century B.C. by the Greek astronomer Thales of Miletus, but was certainly already used as a guide by sailors. In ancient time, Ursa Minor was named the Dragon's wing, and was considered a part of Draco. The dragon's wing as an asterism is now long forgotten. Aratus called the constellation Κυνόσουρα (Kunosoura) meaning "dog's tail". The name was later adapted to Latin as Cynosura. Mythology The constellation of Ursa Minor, when including less visible stars which are still visible to the naked eye, vaguely resembles a bear (with an unusually long tail). In consequence, together with the nearby Ursa Major, it formed the basis of the myth of Callisto. The tail was said to have been lengthened, from that usually expected for a bear, due to the incessant spinning of the bear, by the tail, around the pole. The variant of the story, in which it is Boötes that represents Arcas, Ursa Minor was considered to represent a dog. This is the older tradition which sensibly explains both the length of the tail and the obsolete alternate name of Cynosura (the dog's tail) for Polaris. (It also clarifies the otherwise inexplicable etymology of "cynosure.") In even earlier times, Ursa Minor was considered to be just seven close stars, and mythologically was regarded, as such, as sisters. In early greek mythology, the seven stars in Ursa Minor were considered to be the Hesperides, daughters of Atlas. Together with other constellations in the zodiac sign of Libra (i.e. Boötes, Ursa Major, and Draco) it may have formed the origin of the myth of the apples of the Hesperides, which forms part of The Twelve Labours of Herakles. To many other cultures Ursa Minor was the Hole in which the earth's axle found its bearing. In Hindu mythology, the Pole Star is Dhruva (the word means pole today) and there is a story behind him becoming a star. Notable and named stars BD F Names and other designations Mag. Ly away Comments α 1 Polaris, Alpha Ursae Minoris, Pole Star, Lodestar, Alruccabah, Cynosura, Phoenice, Tramontana, Angel Stern, Navigatoria, Star of Arcady, Yilduz, Mismar, Polyarnaya 1.97 431 < cynosūra < κυνόσουρα "The dog’s tail" Cepheid variable β 7 Beta Ursae Minoris, Kochab, Kokab, Kochah 2.07 126 < الكوكب الشمالي az-kawkab aš-šamāliyy The north star (lit. heavenly body) [named when it was the pole star] γ 13 Gamma Ursae Minoris, Pherkad, Pherkad Major 3.00 480 < فرقد farqad calf < ? alifa al farkadayn The dim one of the two calves [along with the brighter Kochab]. Delta Scuti type variable star ε 22 Epsilon Ursae Minoris 4.21 347 RS Canum Venaticorum type variable star 2 2 Ursae Minoris 4.24 5 5 Ursae Minoris 4.25 ζ 16 Zeta Ursae Minoris, Alifa al Farkadain 4.29 376 < ? alifa al farkadayn The dim one of the two calves [originally applied to Pherkad] δ 23 Delta Ursae Minoris, Yildun, Gildun, Vildiur, Yilduz, Pherkard 4.36 183 < Turkish yıldız star 4 4 Ursae Minoris 4.80 η 21 Eta Ursae Minoris, Anwar al Farkadain, Alasco 4.95 97.3 < ? anwar al-farkadayn The light [bright] one of the two calves [originally applied to Kochab] θ 15 Theta Ursae Minoris 5.00 830 11 11 Ursae Minoris, Pherkad Minor 5.02 19 19 Ursae Minoris 5.48 18 18 Ursae Minoris 5.73 24 24 Ursae Minoris 5.78 λ Lambda Ursae Minoris 6.31 880 20 20 Ursae Minoris 6.36 3 3 Ursae Minoris 6.43 π¹ Pi-1 Ursae Minoris 6.58 70.8 double star; component magnitudes: 6.9, 7.8 9 9 Ursae Minoris 6.64 8 8 Ursae Minoris 6.83 π² Pi-2 Ursae Minoris 6.89 384 14 14 Ursae Minoris 7.52 Source: The Bright Star Catalogue, 5th Revised Ed., The Hipparcos Catalogue, ESA SP-1200 See also External links Wikimedia Commons has media related to: [Special] [The Deep Photographic Guide to the Constellations: Ursa Minor]   From Wikipedia, the Free Encyclopedia. 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