Ursa Minor
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| Abbreviation: | UMi |
| Genitive: | Ursae Minoris |
| Symbology: | The Little Bear |
| Right ascension: | 15 h |
| Declination: | 75° |
| Area: | sq. deg. (56th) |
| Main stars: | 7 |
| Bayer/Flamsteed stars: | 23 |
| Stars with known planets: | 0 |
| Bright stars: | 2 |
| Nearby stars: | 0 |
| Brightest star: | Polaris (2.02m) |
| Nearest star: | π1 UMi (70.8 ly) |
| Messier objects: | 0 |
| 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 |
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Ursa Minor (IPA: /ˈəːsə ˈmʌɪnə/) is a constellation in the northern sky, the name of which means Smaller 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.[1]
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[edit] Notable features
Ursa Minor is 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.
Polaris (α UMi), the brightest star in the constellation, is a yellow supergiant shining at the brightness of 2.02m. It belongs to the rare class of Cepheid variable stars. Only a bit less bright is β UMi (Kochab), a 2.08m orange giant star.
The four stars in the "bowl" of the little dipper are unusual in that they are of second, third, fourth and fifth magnitude. Hence they provide an easy guide to determining what magnitude stars are visible, useful for city dwellers or testing your eyesight.
[edit] Notable deep sky objects
Ursa Minor Dwarf, a dwarf galaxy is located in the area of the constellation.
[edit] History
This constellation is said to have been introduced in the 6th century BC by the Greek astronomer Thales of Miletus, but was certainly already used as a guide by sailors.[citation needed]
In ancient times, 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.[citation needed] Aratus called the constellation Κυνόσουρα (Kunosoura) meaning "dog's tail". The name was later adapted to Latin as Cynosura.
[edit] 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 Heracles.
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.
[edit] See also
[edit] References
- ^ Guilherme de Almeida (2004). Navigating the Night Sky: How to Identify the Stars and Constellations. Springer. ISBN 1852337370.
[edit] External links
| The 88 modern Constellations |
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| Andromeda • Antlia • Apus • Aquarius • Aquila • Ara • Aries • Auriga • Boötes • Caelum • Camelopardalis • Cancer • Canes Venatici • Canis Major • Canis Minor • Capricornus • Carina • Cassiopeia • Centaurus • Cepheus • Cetus • Chamaeleon • Circinus • Columba • Coma Berenices • Corona Australis • Corona Borealis • Corvus • Crater • Crux • Cygnus • Delphinus • Dorado • Draco • Equuleus • Eridanus • Fornax • Gemini • Grus • Hercules • Horologium • Hydra • Hydrus • Indus • Lacerta • Leo • Leo Minor • Lepus • Libra • Lupus • Lynx • Lyra • Mensa • Microscopium • Monoceros • Musca • Norma • Octans • Ophiuchus • Orion • Pavo • Pegasus • Perseus • Phoenix • Pictor • Pisces • Piscis Austrinus • Puppis • Pyxis • Reticulum • Sagitta • Sagittarius • Scorpius • Sculptor • Scutum • Serpens • Sextans • Taurus • Telescopium • Triangulum • Triangulum Australe • Tucana • Ursa Major • Ursa Minor • Vela • Virgo • Volans • Vulpecula |
