Ursa Minor

Ursa Minor

Constellation
List of stars in Ursa Minor
Abbreviation	UMi
Genitive	Ursae Minoris
Pronunciation	/ˌɜrsə ˈmaɪnər/, genitive /ˌɜrsiː mɨˈnɒrɨs/
Symbolism	The Little Bear
Right ascension	15
Declination	+75
Area	256 sq. deg. (56th)
Main stars	7
Bayer/Flamsteed stars	23
Stars with known planets	1
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.

Ursa Minor, often called the Little Dipper, is a constellation in the northern sky. Its name is Latin for 'little bear', contrasting with Ursa Major, the Great Bear. Like the big dipper, the handle of the little dipper is the tail of the "little bear". It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor 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]

Notable features

Stars

Ursa Minor is colloquially known as the Little Dipper because its seven brightest stars seem to form the shape of a dipper (ladle or scoop). 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 2.02 apparent magnitude . It belongs to the rare class of Cepheid variable stars. Only a bit less bright is β UMi (Kochab), a 2.08 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.

Named stars

Deep sky objects

Ursa Minor Dwarf, a dwarf galaxy, is located in the area of the constellation.

History and mythology

Ursa Minor, with Draco looping around it, as depicted in Urania's Mirror, a set of constellation cards published in London c.1825

Ursa Minor is commonly visualized as a baby bear with an unusually long tail. The tail was said to have been lengthened from that usually expected for a bear, due to its being held by the tail and spun around the pole.(The center of the sky)

Ursa Minor and Ursa Major were related by the Greeks to the myth of Callisto and Arcas. However, in a 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, the North Star.^[2]

Previously, Ursa Minor was considered to be just seven close stars, mythologically regarded as sisters. In early Greek mythology, the seven stars of the Little Dipper were considered to be the Hesperides, daughters of Atlas. Together with the nearby constellations of 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 Labours of Hercules.^{[original research?]}

In earliest 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]}

In 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.^{[citation needed]}

See also

• Ursa Major
• Ursa Minor Beta, a place in The Hitchhiker's Guide to the Galaxy

Citations

References

• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.

External links

Wikimedia Commons has media related to: Ursa Minor

• The Deep Photographic Guide to the Constellations: Ursa Minor
• Star Tales – Ursa Minor

Coordinates: 15^h 00^m 00^s, +75° 00′ 00″