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Ursa Major and Ursa Minor
Ursa Major and Ursa Minor [Lat.,=the great bear; the little bear], two conspicuous northern constellations . Known to many peoples from ancient times, these constellations have had various names; the configuration of the seven brightest stars has been called the Bear, Septentriones (the seven plowing oxen), the Plow, Charles's Wain, and the Wagon. Ursa Minor was once known as Cynosura (from the Greek for "dog's tail" ). In the United States part of Ursa Major is called the Big Dipper (or the Drinking Gourd) and part of Ursa Minor, the Little Dipper. Four of the seven bright stars in the Big Dipper form the bowl and three the handle; five of these stars are of second magnitude. The middle star in the handle of the Big Dipper is Mizar (Zeta Ursae Majoris). A fainter star, Alcor, which appears to be near Mizar, was observed from ancient times. These two stars are sometimes called a double star, but since they do not revolve around a common center of gravity they are not true doubles. Mizar itself is, however, a visual binary star and was the first to be recognized as such—by G. B. Riccioli in 1650. It was also the first spectroscopic binary to be discovered; this observation resulted from studies of the spectrum of the brighter component of Mizar, which revealed it as a binary consisting of a pair of stars of almost equal brightness. The two end stars in the bowl of the Big Dipper are known as the Pointers. A line extending through them to about five times the distance between them leads to the polestar ( Polaris , or the North Star). Polaris is at the extreme end of the Little Dipper. Including Polaris there are three stars in the handle of the Little Dipper and four forming the bowl. The handles of the two Dippers extend in opposite directions, and when one bowl is upright the other is inverted. Ursa Major reaches its highest point in the evening sky in April and Ursa Minor its highest point in June. However, for observers in the middle and northern latitudes of the Northern Hemisphere both constellations are circumpolar and thus are visible throughout the year. |
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"Ursa Major and Ursa Minor." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Ursa Major and Ursa Minor." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1E1-UrsaMajo.html "Ursa Major and Ursa Minor." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-UrsaMajo.html |
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Ursa Major
Ursa Major (abbr. UMa, gen. Ursae Majoris) The third-largest constellation, lying in the northern sky and better known as the Great Bear. Its seven main stars make up the familiar shape known as the Plough or Big Dipper. Its two brightest stars are Dubhe (Alpha Ursae Majoris) and Alioth (Epsilon Ursae Majoris), both magnitude 1.8. Mizar (Zeta Ursae Majoris) is a famous naked-eye double. Xi Ursae Majoris is a binary of magnitudes 4.3 and 4.8 and a period of 60 years; it was the first binary to have its orbit computed. Lalande 21185 is the fourth-closest star to the Sun. M81 and M101 are spiral galaxies of 7th and 8th magnitudes. M82 is an 8th-magnitude peculiar galaxy, now thought to be a spiral seen edge-on that is undergoing a burst of star formation. M97 is the Owl Nebula.
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"Ursa Major." A Dictionary of Astronomy. 1997. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Ursa Major." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O80-UrsaMajor.html "Ursa Major." A Dictionary of Astronomy. 1997. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-UrsaMajor.html |
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Ursa Major
Ur·sa Ma·jor / ˈərsə ˈmājər/ Astron. one of the largest and most prominent northern constellations (the Great Bear). The seven brightest stars form a familiar asterism known by various names (esp. the Big Dipper and the Plow) and include the Pointers. ∎ [as genitive] (Ur·sae Ma·jor·is / ˈərsē məˈjôris/ ) used with a preceding letter or numeral to designate a star in this constellation: the star Delta Ursae Majoris. |
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"Ursa Major." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Ursa Major." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O999-ursamajor.html "Ursa Major." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-ursamajor.html |
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Ursa Major Moving Cluster
Ursa Major Moving Cluster A widespread group of stars with similar space velocities, about 14 km/s, which includes five of the seven main members of the Plough (Beta, Gamma, Delta, Epsilon, and Zeta Ursae Majoris). It is the nearest star cluster to us, about half the distance of the Hyades. There is evidence that stars over a much wider area of sky, including Sirius, have similar motions to those in the core of the cluster.
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"Ursa Major Moving Cluster." A Dictionary of Astronomy. 1997. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Ursa Major Moving Cluster." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O80-UrsaMajorMovingCluster.html "Ursa Major Moving Cluster." A Dictionary of Astronomy. 1997. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-UrsaMajorMovingCluster.html |
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Ursa Major
Ursa Major one of the largest and most prominent northern constellations (the Great Bear). The seven brightest stars form a familiar formation variously called the Plough, Big Dipper, or Charles's Wain, and include the Pointers.
Boswell's father, Lord Auchinleck (1706–82) gave the name Ursa Major to Dr Johnson. |
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ELIZABETH KNOWLES. "Ursa Major." The Oxford Dictionary of Phrase and Fable. 2006. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. ELIZABETH KNOWLES. "Ursa Major." The Oxford Dictionary of Phrase and Fable. 2006. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O214-UrsaMajor.html ELIZABETH KNOWLES. "Ursa Major." The Oxford Dictionary of Phrase and Fable. 2006. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O214-UrsaMajor.html |
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Ursa Major
Ursa Major (Great Bear) Northern constellation, whose main pattern, consisting of seven stars, is known as the Plough or Big Dipper. Five of the Plough stars make up a cluster.
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"Ursa Major." World Encyclopedia. 2005. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Ursa Major." World Encyclopedia. 2005. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O142-UrsaMajor.html "Ursa Major." World Encyclopedia. 2005. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-UrsaMajor.html |
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