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Ursa Major

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Ursa Major

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  1. Ursa Major Janna Browning C period

  2. General Facts • Ursa Major is a constellation: a group of stars visibly related to each other in a particular configuration or pattern. An asterism is a pattern of stars seen in Earth's sky which is not an official constellation. • Like constellations, they are composed of stars which are not physically related, often being at significantly different distances from Earth. • An asterism may be composed of stars from one or more constellations. They usually have mostly simple shapes and few stars which make them easy to identify. • Abbreviation: UMa • Genitive: Ursae Majoris • Translation: The Greater Bear • Third largest constellation • Consists of 17 named stars • Nickname: The Great Bear • Contains Big Dipper asterism

  3. History • Ursa Major is one of the most well known constellations in the heavens. • It was one of the 48 constellations listed by Ptolemy. • It contains the famous grouping of stars known as the Big Dipper, which is often the first group of stars learned by people in the northern hemisphere.

  4. History cont’d… • Several other "firsts" are associated with this constellation; • the star Mizar was the first double star to be discovered through a telescope (1662) • the first star to be photographed (1857) • the first star to be identified as a spectroscopic binary (1889) • the star Xi UMa was the first binary star to have its orbit calculated (1828)

  5. Stars in Ursa Major • Alpha UMa (Dubhe: the Bear) is a yellow giant, about 25 times the size of the Sun, and 86 light years away. • Beta UMa (Merak: loin), Gamma UMa(Phecda: thigh), and Delta UMa(Megrez: root [or base] of the tail) are all similar white (A-type) stars, all within 100 light years distance. alpha beta gamma delta

  6. The “Big Dipper” • The constellation Ursa Major contains the group of stars commonly called the Big Dipper. • The handle of the Dipper is the Great Bear's tail and the Dipper's cup is the Bear's flank. • The Big Dipper is not a constellation itself, but an asterism, which is a distinctive group of stars. • Another famous asterism is the Little Dipper in the constellation Ursa Minor.

  7. Compass in the Sky • The Big Dipper has a circumpolar orbit (orbits the north pole). • Because of this, the two outside stars on the asterism’s bowl will always lead the way to Polaris, the North Star. • Even though Polaris is not often exactly North on a compass, it is fairly close and can help you get directions when you are outside at night.

  8. Stars in the Big Dipper • The seven stars in the Big Dipper are named by number, following the Greek alphabet. • These stars don’t move in the same direction, so eventually the dipper shape will become more plough-like and move more southern. • This asterism has formed in only 50,000 years, but over time will dissolve.

  9. Works Cited Dibon, Richard. “Ursa Major.” The Constellations. 2007. 23 Apr. 2007 <‌uma_con.htm>. Dolan, Chris. “The Big Dipper.” Astronomy for Kids. Winter 2006. 23 Apr. 2007 <‌afk/‌constellations/‌bigdipper/>. - - -. “Ursa Major, the Greater Bear.” Ursa Major. 20 Apr. 2007 <‌~dolan/‌constellations/‌constellations/‌Ursa_Major.html>. - - -.“Map of the Big Dipper.” Map. 2006. Astronomy for Kids. 21 Apr. 2007 <>. - - -. “Map of Ursa Major.” Map. 2006. Astronomy for Kids. 21 Apr. 2007 <>. - - -."The Big Dipper and Polaris." Astronomy for Kids. 23 Apr. 2007 <>. - - -.“Ursa Major.” Constellations. 23 Apr. 2007. <>. Raasch, Rick. “URSA MAJOR.” Constellation of the Month. The Texas Astronomical Society. 20 Apr. 2007 <‌~dolan/‌constellations/‌cotm/‌uma.html>. Schmidling, Jack. “Alpha Ursa Minoris (Polaris).” Double Stars. 23 Apr. 2007. Jack Schmidling Productions, Inc. <>. Production by: Janna Browning