genitive / /
|Symbolism||the Great Bear|
|Area||1280 sq. deg. (3rd)|
|Main stars||7, 20|
|Stars with planets||21|
|Stars brighter than 3.00m||7|
|Stars within 10.00 pc (32.62 ly)||8|
|Brightest star||ε UMa (Alioth) (1.76m)|
|Nearest star||Lalande 21185
(8.31 ly, 2.55 pc)
|Meteor showers||Alpha Ursa Majorids
|Visible at latitudes between +90° and −30°.
Best visible at 21:00 (9 p.m.) during the month of April.
Big Dipper or Plough.
Ursa Major (Latin: "Larger Bear"; also known as the Great Bear and Charles' Wain) is a constellation visible throughout the year in most of the northern hemisphere. It can be seen best in the month of April. It is dominated by the widely recognized asterism known as the Big Dipper or the Plough, which is a useful pointer towards the north, and it has mythological significance in numerous world cultures.
The seven brightest stars of Ursa Major form the asterism known as the Big Dipper in the USA and Canada, the Plough in the United Kingdom, the Großer Wagen in Germany & Austria and the Saptarshi in India.
These stars are found along the southwest border of the constellation.
The "Big Dipper" (or "Plough") asterism within Ursa Major is made up of seven bright stars that together comprise one of the best-known patterns in the sky, while also forming the hindquarters and tail of the Great Bear. Starting with the "ladle" portion of the dipper and extending clockwise through the handle, these stars are the following:
Except for Dubhe and Alkaid (Eta Ursae Majoris), the stars of the Big Dipper all have proper motions heading toward a common point in Sagittarius. A few other such stars have been identified, and together they are called the Ursa Major Moving Group.
The stars Merak (β Ursae Majoris) and Dubhe (α Ursae Majoris) are known as the "pointer stars" because they are helpful for finding Polaris, also known as the North Star or Pole Star. By visually tracing a line from Merak through Dubhe and continuing, one's eye will land on Polaris, accurately indicating true north.
47 Ursae Majoris is a Sun-like star with a three-planet system. 47 Ursae Majoris b, discovered in 1996, orbits every 1078 days and is 2.53 times the mass of Jupiter. 47 Ursae Majoris c, discovered in 2001, orbits every 2391 days and is 0.54 times the mass of Jupiter. 47 Ursae Majoris d, discovered in 2010, has an uncertain period, lying between 8907 and 19097 days; it is 1.64 times the mass of Jupiter. The star is of magnitude 5.0 and is approximately 46 light-years from Earth.
Several bright galaxies are found in Ursa Major, including the pair Messier 81 (one of the brightest galaxies in the sky) and Messier 82 above the bear's head, and Pinwheel Galaxy (M101), a spiral northeast of η Ursae Majoris. The spiral galaxies Messier 108 and Messier 109 are also found in this constellation. The bright planetary nebula Owl Nebula (M97) can be found along the bottom of the bowl of the Big Dipper.
M81 is a nearly face-on spiral galaxy 11.8 million light-years from Earth. Like most spiral galaxies, it has a core made up of old stars, with arms filled with young stars and nebulae. Along with M82, it is a part of the galaxy cluster closest to the Local Group.
M101, also called the Pinwheel Galaxy, is a face-on spiral galaxy located 25 million light-years from Earth. It was discovered by Pierre Méchain in 1781. Its spiral arms have regions with extensive star formation and have strong ultraviolet emissions. It has an integrated magnitude of 7.5, making it visible in both binoculars and telescopes, but not to the naked eye.
NGC 2787 is a lenticular galaxy at a distance of 24 million light-years. Unlike most lenticular galaxies, NGC 2787 has a bar at its center. It also has a halo of globular clusters, indicating its age and relative stability.
NGC 3079 is a starburst spiral galaxy located 52 million light-years from Earth. It has a horseshoe-shaped structure at its center that indicates the presence of a supermassive black hole. The structure itself is formed by superwinds from the black hole.
NGC 3310 is another starburst spiral galaxy located 50 million light-years from Earth. Its bright white color is caused by its higher than usual rate of star formation, which began 100 million years ago after a merger. Studies of this and other starburst galaxies have shown that their starburst phase can last for hundreds of millions of years, far longer than was previously assumed.
I Zwicky 18 is a young dwarf galaxy at a distance of 45 million light-years. The youngest known galaxy in the visible universe, I Zwicky 18 is about 4 million years old, about one-thousandth the age of the Solar System. It is filled with star forming regions which are creating many hot, young, blue stars at a very high rate.
HD 80606, a sun-like star in a binary system, orbits a common center of gravity with its partner, HD 80607; the two are separated by 1,200 AU on average. Research conducted in 2003 indicates that its sole planet, HD 80606 b is a future hot Jupiter, modeled to have evolved in a perpendicular orbit around 5 AU from its sun. The 4-Jupiter mass planet is projected to eventually move into a circular, more aligned orbit via the Kozai mechanism. However, it is currently on an incredibly eccentric orbit that ranges from approximately one astronomical unit at its apoapsis and six stellar radii at periapsis.
Ursa Major has been reconstructed as an Indo-European constellation. It was one of the 48 constellations listed by the 2nd century AD astronomer Ptolemy. It is mentioned by such poets as Homer, Spenser, Shakespeare and Tennyson. The Finnish epic Kalevala mentions it, Vincent van Gogh painted it, and Federico Garcia Lorca mentions in his poem "Song for the Moon" written August 1920. In 2009, the American rock band Third Eye Blind named their fourth album, Ursa Major, after the constellation. It may be mentioned in the biblical book of Job, dated between the 7th and 4th centuries BC, although this is disputed.
The constellation of Ursa Major has been seen as a bear by many distinct civilizations. This may stem from a common oral tradition stretching back more than 13,000 years. Using statistical and phylogenetic tools, Julien d'Huy reconstructs the following Palaeolithic state of the story: "There is an animal that is a horned herbivore, especially an elk. One human pursues this ungulate. The hunt locates or get to the sky. The animal is alive when it is transformed into a constellation. It forms the Big Dipper".
In Burmese, Pucwan Tārā (pronounced "bazun taja") is the name of a constellation comprising stars from the head and forelegs of Ursa Major; pucwan is a general term for a crustacean, such as prawn, shrimp, crab, lobster, etc.
In Roman mythology, Jupiter (the king of the gods) lusts after a young woman named Callisto, a nymph of Diana. Juno, Jupiter' jealous wife, transforms the beautiful Callisto into a bear. Callisto, while in bear form, later encounters her son Arcas. Arcas almost shoots the bear, but to avert the tragedy, Jupiter turns them into bears and puts them in the sky, forming Ursa Major and Ursa Minor. Callisto is Ursa Major and her son, Arcas, is Ursa Minor. In ancient times the name of the constellation was Helike, ("turning"), because it turns around the Pole. In Book Two of Lucan it is called Parrhasian Helice, since Callisto came from Parrhasia in Arcadia, where the story is set. The Odyssey notes that it is the sole constellation that never sinks below the horizon and "bathes in the Ocean's waves", so it is used as a celestial reference point for navigation. It is also referred to as the "Wain".
One of the few star groups mentioned in the Bible (Job 9:9; 38:32; — Orion and the Pleiades being others), Ursa Major was also pictured as a bear by the Jewish peoples. ("The Bear" was translated as "Arcturus" in the Vulgate and it persisted in the KJV.)
The Iroquois Native Americans interpreted Alioth, Mizar, and Alkaid as three hunters pursuing the Great Bear. According to one version of their myth, the first hunter (Alioth) is carrying a bow and arrow to strike down the bear. The second hunter (Mizar) carries a large pot — the star Alcor — on his shoulder in which to cook the bear while the third hunter (Alkaid) hauls a pile of firewood to light a fire beneath the pot.
In Hinduism, Ursa Major is known as Saptarshi, each of the stars representing one of the Saptarshis or Seven Sages viz. Bhrigu, Atri, Angirasa, Vasishta, Pulastya, Pulalaha and Kratu. The fact that the two front stars of the constellations point to the pole star is explained as the boon given to the boy sage Dhruva by Lord Vishnu.
In Javanese, as known as "Bintang Kartika". This name comes from Sanskrit which refers "krttikã" the same star cluster. In ancient Javanese this brightest seven stars are known as Lintang Wuluh, literally means "seven stars". This star clusters so popular because its emergence into the start time marker for planting.
In South Korea, the constellation is referred to as "the seven stars of the north". In the related myth, a widow with seven sons found comfort with a widower, but to get to his house required crossing a stream. The seven sons, sympathetic to their mother, placed stepping stones in the river. Their mother, not knowing who put the stones in place, blessed them and, when they died, they became the constellation.
In Theosophy, it is believed the Seven Stars of the Pleiades focus the spiritual energy of the Seven Rays from the Galactic Logos to the Seven Stars of the Great Bear, then to Sirius, then to the Sun, then to the god of Earth (Sanat Kumara), and finally through the seven Masters of the Seven Rays to the human race.
In European star charts, the constellation was visualized with the 'square' of the Big Dipper forming the bear's body and the chain of stars forming the Dipper's "handle" as a long tail. However, bears do not have long tails, and Jewish astronomers considered Alioth, Mizar, and Alkaid instead to be either three cubs following their mother, and the Native Americans as three hunters.
Noted children's book author H. A. Rey, in his 1952 book The Stars: A New Way to See Them, (ISBN 0-395-24830-2) instead had the "bear" image of the constellation, much as Johannes Hevelius had done (as far as the figure of the bear facing "left"), oriented with Alkaid as the tip of the bear's nose, and the "handle" of the Big Dipper part of the constellation forming the outline of the top of the bear's head and neck, rearwards to the shoulder. Because of Rey's book, many amateur astronomers[who?] have come to accept Rey's star chart interpretation of Ursa Major, dropping the idea of the Big Dipper's "handle" as being the hind end of the bear, with a non-natural "tail" extending rearwards.
Ursa Major as depicted in Urania's Mirror, a set of constellation cards published in London c.1825.
Johannes Hevelius drew Ursa Major as if being viewed from outside the celestial sphere.
Ursa Major is also pictured as the Starry Plough, the Irish Flag of Labour, adopted by James Connolly's Irish Citizen Army in 1916, which shows the constellation on a blue background, and on the state flag of Alaska.
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