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50-585: Cetus Dwarf is a dwarf spheroidal galaxy . It lies approximately 2.46 Million light-years from Earth. It is an isolated galaxy of the Local Group , which also contains the Milky Way . All of the most readily observable stars in the galaxy are red giants . The Cetus Dwarf was discovered in 1999 by Alan B. Whiting , George Hau and Mike Irwin and was found to be a member of the Local Group . As of 2000, no known neutral hydrogen gas has been found that

100-453: 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 . M82 is a nearly edgewise galaxy that is interacting gravitationally with M81. It is the brightest infrared galaxy in the sky. SN 2014J , an apparent Type Ia supernova , was observed in M82 on 21 January 2014. M97 , also called

150-460: 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

200-465: A different class of object from globular clusters , which show little to no signs of dark matter. Because of the extremely large amounts of dark matter in dwarf spheroidal galaxies, they may deserve the title "most dark matter-dominated galaxies." Further evidence of the prevalence of dark matter in dSphs includes the case of Fornax dwarf spheroidal galaxy, which can be assumed to be in dynamic equilibrium to estimate mass and amount of dark matter, since

250-538: A leaping 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). W Ursae Majoris

300-449: 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. NGC 4013 is an edge-on spiral galaxy located 55 million light-years from Earth. It has a prominent dust lane and has several visible star forming regions. I Zwicky 18 is a young dwarf galaxy at a distance of 45 million light-years. The youngest-known galaxy in

350-411: A star cluster; however, many astronomers decide this depending on the object's dynamics: If it seems to have more dark matter , then it is likely that it is a dwarf spheroidal galaxy rather than an enormous, faint star cluster . In the current predominantly accepted Lambda cold dark matter cosmological model, the presence of dark matter is often cited as a reason to classify dwarf spheroidal galaxies as

400-476: 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

450-500: 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. Ursa Major covers 1279.66 square degrees or 3.10% of

500-570: 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 ( 9 40 44 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

550-470: 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

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600-687: Is called "bintang jong". 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,

650-609: Is identified as the bow of the great hunter Fávdna (the star Arcturus ). In the main Sámi language, North Sámi , it is called Fávdnadávgi ("Fávdna's Bow") or simply dávggát ("the Bow"). The constellation features prominently in the Sámi anthem , which begins with the words Guhkkin davvin dávggaid vuolde sabmá suolggai Sámieanan , which translates to "Far to the north, under the Bow, the Land of

700-412: Is many times that which can be accounted for by the mass of the stars themselves. Studies reveal that dwarf spheroidal galaxies have a dynamical mass of around 10   M ☉ , which is very large despite the low luminosity of dSph galaxies. Although at fainter luminosities of dwarf spheroidal galaxies, it is not universally agreed upon how to differentiate between a dwarf spheroidal galaxy and

750-522: Is related to the Cetus dwarf galaxy. Dwarf spheroidal galaxy Despite the radii of dSphs being much larger than those of globular clusters , they are much more difficult to find due to their low luminosities and surface brightnesses. Dwarf spheroidal galaxies have a large range of luminosities, and known dwarf spheroidal galaxies span several orders of magnitude of luminosity. Their luminosities are so low that Ursa Minor , Carina , and Draco ,

800-489: Is the prototype of a class of contact binary variable stars , and ranges between 7.75 and 8.48 . 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

850-711: 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

900-569: 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 representing three pairs of footprints of

950-466: The "Wain" or "Plaustrum", a Latin word referring to a ‍horse-drawn ‍cart. In Hinduism , Ursa Major/Big dipper/ Great Bear is known as Saptarshi , each of the stars representing one of the Saptarishis or Seven Sages (Rishis) viz. Bhrigu , Atri , Angiras , Vasishtha , Pulastya , Pulaha , and Kratu . The fact that the two front stars of the constellations point to the pole star is explained as

1000-460: The Big Dipper's stellar configuration mimics the shape of the " Little Dipper ". Two of its 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 it contains or overlaps, is significant to numerous world cultures, often as

1050-647: The Owl Nebula, is a planetary nebula 1,630 light-years from Earth; it has a magnitude of approximately 10. It was discovered in 1781 by Pierre Méchain . 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

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1100-610: The Parrhasian Bear, since Callisto came from Parrhasia in Arcadia , where the story is set. The Greek poet Aratus called the constellation Helike, ("turning" or "twisting"), because it turns around the celestial pole. 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 has also been called

1150-557: The Romans as Diana ). Zeus's jealous wife Hera ( Juno to the Romans) discovers that Callisto has a son named Arcas as the result of her rape by Zeus and transforms Callisto into a bear as a punishment. Callisto, while in bear form, later encounters her son Arcas . Arcas almost spears the bear, but to avert the tragedy Zeus whisks them both into the sky, Callisto as Ursa Major and Arcas as the constellation Boötes . Ovid called Ursa Major

1200-539: The Sámi slowly comes into view." The Bow is an important part of the Sámi traditional narrative about the night sky, in which various hunters try to chase down Sarva , the Great Reindeer, a large constellation that takes up almost half the sky. According to the legend, Fávdna stands ready to fire his Bow every night but hesitates because he might hit Stella Polaris , known as Boahji ("the Rivet"), which would cause

1250-606: 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

1300-560: 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. The Lakota people call the constellation Wičhákhiyuhapi , or "Great Bear". The Wampanoag people (Algonquian) referred to Ursa Major as "maske", meaning "bear" according to Thomas Morton in The New England Canaan. The Wasco-Wishram Native Americans interpreted

1350-429: 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 female, by many distinct civilizations. This may stem from a common oral tradition of Cosmic Hunt myths stretching back more than 13,000 years. Using statistical and phylogenetic tools, Julien d'Huy reconstructs the following Palaeolithic state of

1400-836: 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 Jews . "The Bear" was translated as "Arcturus" in the Vulgate and it persisted in the King James Version of the 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

1450-477: The constellation as five wolves and two bears that were left in the sky by Coyote . To Norse pagans , the Big Dipper was known as Óðins vagn , " Woden 's wagon". Likewise Woden is poetically referred to by Kennings such as vagna verr 'guardian of the wagon' or vagna rúni 'confidant of the wagon' In the Finnish language , the asterism is sometimes called by its old Finnish name, Otava . The meaning of

1500-617: 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

1550-599: The discovery of 11 more dSph galaxies as of 2007 By 2015, many more ultra-faint dSphs were discovered, all satellites of the Milky Way. Nine potentially new dSphs were discovered in the Dark Energy Survey in 2015. Each dSph is named after constellations they are discovered in, such as the Sagittarius dwarf spheroidal galaxy , all of which consist of stars generally much older than 1–2 Gyr that formed over

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1600-400: The faintness of the lowest-luminosity dwarf spheroidal galaxies and the nature of the stars contained within them, some astronomers suggest that dwarf spheroidal galaxies and globular clusters may not be clearly separate and distinct types of objects. Other recent studies, however, have found a distinction in that the total amount of mass inferred from the motions of stars in dwarf spheroidals

1650-657: The gravitational effects of the Milky Way are small. Unlike the Fornax galaxy, there is evidence that the UMa2, a dwarf spheroidal galaxy in the Ursa Major constellation , experiences strong tidal disturbances from the Milky Way. A topic of research is how much the internal dynamics of dwarf spheroidal galaxies are affected by the gravitational tidal dynamics of the galaxy they are orbiting. In other words, dwarf spheroidal galaxies could be prevented from achieving equilibrium due to

1700-538: The gravitational field of the Milky Way or other galaxy that they orbit. For example, the Sextans dwarf spheroidal galaxy has a velocity dispersion of 7.9±1.3 km/s, which is a velocity dispersion that could not be explained solely by its stellar mass according to the Virial Theorem . Similar to Sextans, previous studies of Hercules dwarf spheroidal galaxy reveal that its orbital path does not correspond to

1750-400: 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

1800-446: The known dwarf spheroidal galaxies with the lowest luminosities, have mass-to-light ratios (M/L) greater than that of the Milky Way. Dwarf spheroidals also have little to no gas with no obvious signs of recent star formation. Within the Local Group , dSphs are primarily found near the Milky Way and M31 . The first dwarf spheroidal galaxies discovered were Sculptor and Fornax in 1938. The Sloan Digital Sky Survey has resulted in

1850-525: The lesser bear. In antiquity , it was one of the original 48 constellations listed by Ptolemy in the 2nd century AD, drawing on earlier works by Greek, Egyptian, Babylonian, and Assyrian astronomers. 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,

1900-593: The mass contained in Hercules. Furthermore, there is evidence that the UMa2, a dwarf spheroidal galaxy in the Ursa Major constellation , experiences strong tidal disturbances from the Milky Way. Ursa Major Ursa Major , 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) bear", referring to and contrasting it with nearby Ursa Minor ,

1950-412: 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 2950 is a lenticular galaxy located 60 million light-years from Earth. NGC 3000 is a double star, and catalogued as a nebula-type object. NGC 3079

2000-550: 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 the Sámi languages of Northern Europe, part of the constellation (i.e. the Big Dipper minus Dubhe and Merak ,

2050-463: 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

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2100-486: 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 Alkaid . 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

2150-414: The seven stars had a specific name, often coming themselves from ancient China: In Shinto , the seven largest stars of Ursa Major belong to Ame-no-Minakanushi , the oldest and most powerful of all kami . 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

2200-470: The sky to collapse and end the world. In Burmese , Pucwan Tārā (ပုဇွန် တာရာ, [bəzʊ̀ɴ tàjà] ) 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 Javanese , it is known as "lintang jong", which means "the jong constellation". Likewise, in Malay it

2250-497: The span of many gigayears. For example, 98% of the stars in the Carina dwarf spheroidal galaxy are older than 2 Gyr, formed over the course of three bursts around 3, 7 and 13 Gyr ago. The stars in Carina have also been found to be metal-poor. This is unlike star clusters because, while star clusters have stars which formed more or less the same time, dwarf spheroidal galaxies experience multiple bursts of star formation. Because of

2300-461: 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 Greek mythology , Zeus (the king of the gods, known as Jupiter in Roman mythology ) lusts after a young woman named Callisto , a nymph of Artemis (known to

2350-471: 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 08 08.3 and 14 29.0 and the declination coordinates of +28.30° and +73.14°. Ursa Major borders eight other constellations: Draco to

2400-648: 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

2450-483: 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. The Hubble Deep Field is located to the northeast of δ Ursae Majoris . HD 80606 , a sun-like star in a binary system, orbits a common center of gravity with its partner, HD 80607 ;

2500-548: Was one of the 48 constellations listed by the 2nd century AD astronomer Ptolemy in his Almagest , who called it Arktos Megale. 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

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