Ursa Major (/ˈɜːrsə ˈmeɪdʒər/; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) she-bear," referring to and contrasting it with nearby Ursa Minor, the lesser bear. In antiquity, it was one of the original 48 constellations listed by Ptolemy in the 2nd century AD. Today it is the third largest of the 88 modern constellations.
Ursa Major is primarily known from the asterism of its main seven stars, which has been called the "Big Dipper," "the Wagon," "Charles's Wain," or "the Plough," among other names. In particular, the Big Dipper's stellar configuration mimics the shape of the "Little Dipper." Its two brightest stars, named Dubhe and Merak (α Ursae Majoris and β Ursae Majoris), can be used as the navigational pointer towards the place of the current northern pole star, Polaris in Ursa Minor.
Ursa Major, along with asterisms that incorporate or comprise it, is significant to numerous world cultures, often as a symbol of the north. Its depiction on the flag of Alaska is a modern example of such symbolism.
Ursa Major is visible throughout the year from most of the northern hemisphere, and appears circumpolar above the mid-northern latitudes. From southern temperate latitudes, the main asterism is invisible, but the southern parts of the constellation can still be viewed.
genitive /ˌɜːrsiː məˈdʒɒrɪs/
|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)|
|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.
The Big Dipper or Plough
Ursa Major covers 1279.66 square degrees or 3.10% of the total sky, making it the third largest constellation. In 1930, Eugène Delporte set its official International Astronomical Union (IAU) constellation boundaries, defining it as a 28-sided irregular polygon. In the equatorial coordinate system, the constellation stretches between the right ascension coordinates of 08h 08.3m and 14h 29.0m and the declination coordinates of +28.30° and +73.14°. Ursa Major borders eight other constellations: Draco to the north and northeast, Boötes to the east, Canes Venatici to the east and southeast, Coma Berenices to the southeast, Leo and Leo Minor to the south, Lynx to the southwest and Camelopardalis to the northwest. The three-letter constellation abbreviation 'UMa' was adopted by the IAU in 1922.
The outline of the seven bright stars of Ursa Major form the asterism known as the "Big Dipper" in the United States and Canada, while in the United Kingdom it is called the Plough or (historically) Charles' Wain . Six of the seven stars are of second magnitude or higher, and it forms one of the best-known patterns in the sky. As many of its common names allude, its shape is said to resemble a ladle, an agricultural plough, or wagon. In the context of Ursa Major, they are commonly drawn to represent the hindquarters and tail of the Great Bear. Starting with the "ladle" portion of the dipper and extending clockwise (eastward in the sky) through the handle, these stars are the following:
Except for Dubhe and Alkaid, 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 (1 unit) and continuing for 5 units, one's eye will land on Polaris, accurately indicating true north.
Another asterism known as the "Three Leaps of the Gazelle" is recognized in Arab culture. It is a series of three pairs of stars found along the southern border of the constellation. From southeast to southwest, the "first leap", comprising ν and ξ Ursae Majoris (Alula Borealis and Australis, respectively); the "second leap", comprising λ and μ Ursae Majoris (Tania Borealis and Australis); and the "third leap", comprising ι and κ Ursae Majoris, (Talitha Borealis and Australis respectively).
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.
The star TYC 3429-697-1 ( 9h 40m 44s 48° 14′ 2″), located to the east of θ Ursae Majoris and to the southwest of the "Big Dipper") has been recognized as the state star of Delaware, and is informally known as the Delaware Diamond.
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 in his Almagest, who called it Arktos Megale.[a] It is mentioned by such poets as Homer, Spenser, Shakespeare, Tennyson and also by Federico Garcia Lorca, in "Song for the Moon". Ancient Finnish poetry also refers to the constellation, and it features in the painting Starry Night Over the Rhône by Vincent van Gogh. It may be mentioned in the biblical book of Job, dated between the 7th and 4th centuries BC, although this is often disputed.
The constellation of Ursa Major has been seen as a bear, usually a female 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 Roman mythology, Jupiter (the king of the gods) lusts after a young woman named Callisto, a nymph of Diana. Juno, Jupiter's jealous wife, discovers that Callisto has a son named Arcas, and believes it is by Jupiter. Juno then transforms the beautiful Callisto into a bear so she no longer attracts Jupiter. Callisto, while in bear form, later encounters her son Arcas. Arcas almost shoots the bear, but to avert the tragedy, Jupiter turns Arcas into a bear too and puts them both in the sky, forming Ursa Major and Ursa Minor. Callisto is Ursa Major and her son, Arcas, is Ursa Minor. An alternate version has Arcas become the constellation Boötes.
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 called the "Wain."
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.
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 King James Bible.
In China and Japan, the Big Dipper is called the "North Dipper" 北斗 (Chinese: běidǒu, Japanese: hokuto), and in ancient times, each one of the seven stars had a specific name, often coming themselves from ancient China:
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.
The Iroquois 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 the Finnish language, the asterism is sometimes called by its old Finnish name, Otava. The meaning of the name has been almost forgotten in Modern Finnish; it means a salmon weir. Ancient Finns believed the bear (Ursus arctos) was lowered to earth in a golden basket off the Ursa Major, and when a bear was killed, its head was positioned on a tree to allow the bear's spirit to return to Ursa Major.
In Burmese, Pucwan Tārā (ပုဇွန် တာရာ, pronounced "bazun taya") is the name of a constellation comprising stars from the head and forelegs of Ursa Major; pucwan (ပုဇွန်) is a general term for a crustacean, such as prawn, shrimp, crab, lobster, etc.
In Theosophy, it is believed that 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 three cubs following their mother, while the Native Americans saw them 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) had a different asterism in mind for Ursa Major, that instead had the "bear" image of the constellation 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, potentially giving it the longer head and neck of a polar bear.
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; on the state flag of Alaska; and on the House of Bernadotte's variation of the coat of arms of Sweden. The seven stars on a red background of the flag of the Community of Madrid, Spain, may be the stars of the Plough asterism (or of Ursa Minor). The same can be said of the seven stars pictured in the bordure azure of the coat of arms of Madrid, capital of that country.
The most solidly 'reconstructed' Indo-European constellation is Ursa Major, which is designated as 'The Bear' (Chapter 9) in Greek and Sanskrit (Latin may be a borrowing here), although even the latter identification has been challenged.
The Big Dipper (US, Canada) or the Plough (UK, Ireland) is a large asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" or "body" and three define a "handle" or "head". It is recognized as a distinct grouping in many cultures.
The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper (Little Bear), can be located by extending an imaginary line through the front two stars of the asterism, Merak (β) and Dubhe (α). This makes it useful in celestial navigation.Delta Ursae Majoris
Delta Ursae Majoris (δ Ursae Majoris, abbreviated Delta UMa, δ UMa), formally named Megrez , is a star in the northern circumpolar constellation of Ursa Major. With an apparent magnitude of +3.3, it is the dimmest of the seven stars in the Big Dipper asterism. Parallax measurements yield a distance estimate of 80.5 light-years (24.7 parsecs) from the Sun.Herschel 400 Catalogue
The Herschel 400 catalogue is a subset of William Herschel's original Catalogue of Nebulae and Clusters of Stars, selected by Brenda F. Guzman (Branchett), Lydel Guzman, Paul Jones, James Morrison, Peggy Taylor and Sara Saey of the Ancient City Astronomy Club in St. Augustine, Florida, United States c. 1980. They decided to generate the list after reading a letter published in Sky & Telescope by James Mullaney of Pittsburgh, Pennsylvania, USA.In this letter Mr. Mullaney suggested that William Herschel's original catalogue of 2,500 objects would be an excellent basis for deep sky object selection for amateur astronomers looking for a challenge after completing the Messier Catalogue.
The Herschel 400 is a subset of John Herschel's General Catalogue of Nebulae and Clusters published in 1864 of 5,000 objects, and hence also of the New General Catalogue.
The catalogue forms the basis of the Astronomical League's Herschel 400 club. In 1997, another subset of 400 Herschel objects was selected by the Rose City Astronomers of Portland, Oregon as the Herschel II list, which forms the basis of the Astronomical League's Herschel II Program.List of spiral galaxies
A spiral galaxy is a type of galaxy characterized by a central bulge of old Population II stars surrounded by a rotating disc of younger Population I stars. A spiral galaxy maintains its spirals arms due to density wave theory.List of stars in Ursa Major
This is the list of notable stars in the constellation Ursa Major, sorted by decreasing brightness.Lists of constellations
The following lists of constellations are available:
Modern constellations - a list of the current constellations.
Former constellations - a list of former constellations.
Chinese constellations - traditional Chinese astronomy constellations.
List of Nakshatras - sectors along the moon's ecliptic.NGC 4013
NGC 4013 is an edge-on barred spiral galaxy about 55 million light-years away in the constellation Ursa Major. The disk of NGC 4013 shows a distinct "peanut"-shaped bulge in long exposure photographs that N-body computer simulations suggest is consistent with a stellar bar seen perpendicular to the line of sight.
A recent deep color image of NGC 4013 revealed a looping tidal stream of stars extending over 80 thousand light-years from the Galactic Center. This structure is thought to be the remnants of a smaller galaxy that was torn apart by tidal forces as it collided with NGC 4013.Supernova SN 1989Z was discovered on December 30, 1989 at apparent magnitude 12.NGC 4013 is a member of the Ursa Major Cluster.NGC 4051
NGC 4051 is an intermediate spiral galaxy in the constellation of Ursa Major. It was discovered on 6 February 1788 by John Herschel.NGC 4051 contains a supermassive black hole with a mass of 1.73 million M☉. This galaxy was studied by the Multicolor Active Galactic Nuclei Monitoring 2m telescope. Several supernovae have been discovered in NGC 4051: SN 1983I, SN 2010br, and SN 2003ie.The galaxy is a Seyfert galaxy that emits bright X-rays. However, in early 1998 the X-ray emission ceased as observed in by the Beppo-SAX satellite.NGC 4051 is a member of the Ursa Major Cluster.NGC 4088
NGC 4088 is an intermediate spiral galaxy in the constellation Ursa Major. The galaxy forms a physical pair with NGC 4085, which is located 11′ away.NGC 4088 is a grand design spiral galaxy. This means that the spiral arms in the galaxy's disk are sharply defined. In visible light, one of the spiral arms appears to have a disconnected segment. Halton Arp included this galaxy in the Atlas of Peculiar Galaxies as one of several examples where this phenomenon occurs.NGC 4088 and NGC 4085 are members of the M109 Group, a group of galaxies located in the constellation Ursa Major. This large group contains between 41 and 58 galaxies, including the spiral galaxy M109.NGC 4100
NGC 4100 is a spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on Mar 9, 1788.NGC 4102
NGC 4102 is an intermediate spiral galaxy located in the northern constellation of Ursa Major. The galaxy contains a LINER region and a starburst region. The starburst region is 1,000 ly (310 pc) in diameter containing some 3 billion solar masses.NGC 4144
NGC 4144 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on Apr 10, 1788.NGC 4145
NGC 4145 is a barred spiral galaxy located in the Ursa Major galaxy cluster, 68 million light years from the Earth. The galaxy has little star formation, except on its outer edges. Due to the loss of energy that occurs without star formation, some astronomers predict that the galaxy will degenerate into a lenticular galaxy in the near future. However, the galaxy's interaction with NGC 4151 may "maintain [its] star formation".NGC 4194
NGC 4194, the Medusa merger, is a pair of interacting galaxies in the constellation Ursa Major.
A region of extreme star formation 500 ly (150 pc) across exists in the center of the Eye of Medusa, the central gas-rich region.NGC 4605
NGC 4605 is a peculiar barred spiral galaxy in the constellation Ursa Major.Ursa Major (sculpture)
Ursa Major is a public art work by artist William Underhill located at the Lynden Sculpture Garden near Milwaukee, Wisconsin. The trapezoidal abstract sculpture is made of Cor-Ten steel; it is installed on the lawn.Ursa Major II Dwarf
Ursa Major II Dwarf (UMa II dSph) is a dwarf spheroidal galaxy situated in the Ursa Major constellation and discovered in 2006 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located approximately 30 kpc from the Sun and moves towards the Sun with the velocity of about 116 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical (ratio of axes ~ 2:1) shape with the half-light radius of about 140 pc.Ursa Major II is one of the smallest and faintest satellites of the Milky Way—its integrated luminosity is about 4000 times that of the Sun (absolute visible magnitude of about −4.2), which is much lower than the luminosity of the majority of globular clusters. Uma II is even less luminous than some stars, like Canopus in the Milky Way. It is comparable in luminosity to Bellatrix in Orion. However, its mass is about 5 million solar masses, which means that galaxy's mass to light ratio is around 2000. This may be an overestimate as the galaxy has somewhat irregular shape and may be in process of tidal disruption.The stellar population of Uma II consists mainly of old stars formed at least 10 billion years ago. The metallicity of these old stars is also very low at [Fe/H] ≈ −2.44 ± 0.06, which means that they contain 300 times less heavy elements than the Sun. The stars of Uma II were probably among the first stars to form in the Universe. Currently there is no star formation in Uma II. The measurements have so far failed to detect any neutral hydrogen in it—the upper limit is only 562 solar masses.Ursa Major I Dwarf
Ursa Major I Dwarf (UMa I dSph) is a dwarf spheroidal galaxy orbiting the Milky Way galaxy. Its discovery was revealed by Beth Willman et al. in 2005.Being a small dwarf galaxy, it measures only a few thousand light-years in diameter. As of 2006, it is the third least luminous galaxy known (discounting possible dark galaxies such as VIRGOHI21 in the Virgo cluster of galaxies), after the Boötes Dwarf (absolute magnitude −5.7) and the more recently discovered Ursa Major II Dwarf (absolute magnitude −3.8). The absolute magnitude of the galaxy is estimated to be only −6.75, meaning that it is less luminous than some stars, like Deneb in the Milky Way. It is comparable in luminosity to Rigel. It has been described as similar to the Sextans Dwarf Galaxy. Both galaxies are ancient and metal-deficient.
It estimated to be located at a distance of about 330,000 light-years (100 kpc) from the Earth. That is about twice the distance to the Large Magellanic Cloud; the largest and most luminous satellite galaxy of the Milky Way.
There was another object called "Ursa Major Dwarf", discovered by Edwin Hubble in 1949. It was designated as Palomar 4. Due to its peculiar look, it was temporarily suspected to be either a dwarf spheroidal or elliptical galaxy. However, it has since been found to be a very distant (about 360,000 ly) globular cluster belonging to our galaxy.Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is a nearby stellar moving group – a set of stars with common velocities in space and thought to have a common origin in space and time. In the case of the Ursa Major group, all the stars formed about 300 million years ago. Its core is located roughly 80 light years away. It is rich in bright stars including most of the stars of the Big Dipper.
Stars of Ursa Major