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Square Of Pegasus
Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and is one of the IAU designated constellations, 88 constellations recognised today. With an apparent magnitude varying between 2.37 and 2.45, the brightest star in Pegasus is the orange supergiant Epsilon Pegasi, also known as Enif, which marks the horse's muzzle. Alpha Pegasi, Alpha (Markab), Beta Pegasi, Beta (Scheat), and Gamma Pegasi, Gamma (Algenib), together with Alpha Andromedae (Alpheratz) form the large Asterism (astronomy), asterism known as the ''Square of Pegasus''. Twelve star systems have been found to have exoplanets. 51 Pegasi was the first Sun-like star discovered to have an exoplanet companion. Mythology The Babylonian constellation IKU (field) had four stars of which three were later part of the Greek constellation ''Hippos'' (Pegasus). Pegasus, in Greek mythology, was a winge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Etymology and usage For many centuries, the word "wing", from the Old Norse ''vængr'', referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical cosmology, nature of the world, the lives and activities of List of Greek mythological figures, deities, Greek hero cult, heroes, and List of Greek mythological creatures, mythological creatures, and the origins and significance of the ancient Greeks' own cult (religious practice), cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself. The Greek myths were initially propagated in an oral tradition, oral-poetic tradition most likely by Minoan civilization, Minoan and Mycenaean Greece, Mycenaean singers starting in the 18th century BC; eventually the myths of the heroes of the Trojan War and its after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medusa
In Greek mythology, Medusa (; Ancient Greek: Μέδουσα "guardian, protectress"), also called Gorgo, was one of the three monstrous Gorgons, generally described as winged human females with living venomous snakes in place of hair. Those who gazed into her eyes would turn to stone. Most sources describe her as the daughter of Phorcys and Ceto, although the author Hyginus makes her the daughter of Gorgon and Ceto. Medusa was beheaded by the Greek hero Perseus, who then used her head, which retained its ability to turn onlookers to stone, as a weapon until he gave it to the goddess Athena to place on her shield. In classical antiquity, the image of the head of Medusa appeared in the evil-averting device known as the ''Gorgoneion''. According to Hesiod and Aeschylus, she lived and died on Sarpedon, somewhere near Cisthene. The 2nd-century BC novelist Dionysios Skytobrachion puts her somewhere in Libya, where Herodotus had said the Berbers originated her myth as part of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perseus
In Greek mythology, Perseus (Help:IPA/English, /ˈpɜːrsiəs, -sjuːs/; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer of monsters before the days of Heracles. He beheaded the Gorgon Medusa for Polydectes and saved Andromeda (mythology), Andromeda from the sea monster Cetus (mythology), Cetus. He was the son of Zeus and the mortal Danaë, as well as the half-brother and great-grandfather of Heracles (as they were both children of Zeus, and Heracles' mother was descended from Perseus). Etymology Because of the obscurity of the name "Perseus" and the legendary character of its bearer, most etymologists presume that it might be pre-Greek; however, the name of Perseus's native city was Greek and so were the names of his wife and relatives. There is some idea that it descended into Greek from the Proto-Indo-Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocrene
In Greek mythology, Hippocrene ( grc-gre, Ἵππου κρήνη or Ἱπποκρήνη or Ἱππουκρήνη) was a spring on Mt. Helicon. It was sacred to the Muses and formed when Pegasus struck his hoof into the ground, whence its name which literally translates as "Steed/Horse's Fountain". The water was supposed to bring forth poetic inspiration when imbibed. Sources Hesiod refers to the horse's well on Helicon in his ''Theogony''. And after they have washed their tender skin in Permessus or Hippocrene or holy Olmeidus, they perform choral dances on highest Helicon, beautiful, lovely ones, and move nimbly with their feet. John Keats refers to Hippocrene in his poem "Ode to a Nightingale"."Ode to a Nightingale": O for a beaker full of the warm South Full of the true, the blushful ''Hippocrene'', With beaded bubbles winking at the brim, And purple-stained mouth; That I might drink, and leave the world unseen, And with thee fade away into the forest dim: Henry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
51 Pegasi
51 Pegasi (abbreviated 51 Peg), formally named Helvetios , is a Sun-like star located from Earth in the constellation of Pegasus. It was the first main-sequence star found to have an exoplanet (designated 51 Pegasi b, officially named Dimidium, formerly unofficially dubbed ''Bellerophon'') orbiting it. Properties The star's apparent magnitude is 5.49, making it visible with the naked eye under suitable viewing conditions. 51 Pegasi was listed as a standard star for the spectral type G2IV in the 1989 ''The Perkins catalog of revised MK types for the cooler stars''. Historically, it was generally given a stellar classification of G5V, and even in more modern catalogues it is usually listed as a main-sequence star. It is generally considered to still be generating energy through the thermonuclear fusion of hydrogen at its core, but to be in a more evolved state than the Sun. The effective temperature of the chromosphere is about , giving 51 Pegasi the characteristic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Andromedae
Alpha Andromedae (α Andromedae, abbreviated Alpha And or α And), officially named Alpheratz , is 97 light-years from the Sun and is the brightest star in the constellation of Andromeda when Beta Andromedae undergoes its periodical dimming. Immediately northeast of the constellation of Pegasus, it is the upper left star of the Great Square of Pegasus. Although it appears to the naked eye as a single star, with overall apparent visual magnitude +2.06, it is actually a binary system composed of two stars in close orbit. The chemical composition of the brighter of the two stars is unusual as it is a mercury-manganese star whose atmosphere contains abnormally high levels of mercury, manganese, and other elements, including gallium and xenon.Alpheratz, Kaler Star2/14/2013 It is the brightest mercury-manganese star known. Nomenclature ''α Andromedae'' ( Latinisation of names, Latinised to ''Alpha Andromedae'') is the star's Bayer designation. Ptolemy considered t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Pegasi
Gamma Pegasi is a star in the constellation of Pegasus, located at the southeast corner of the asterism known as the Great Square. It has the formal name Algenib ; the Bayer designation Gamma Pegasi is Latinized from γ Pegasi and abbreviated Gamma Peg or γ Peg. The average apparent visual magnitude of +2.84 makes this the fourth-brightest star in the constellation. The distance to this star has been measured using the parallax technique, yielding a value of roughly . Nomenclature ''Gamma Pegasi'' is the star's Bayer designation. Although it also had the traditional name ''Algenib'', this name was also used for Alpha Persei. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Algenib'' for this star (Alpha Persei was given the name ''Mirfak''). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Pegasi
Beta Pegasi (β Pegasi, abbreviated Beta Peg, β Peg), formally named Scheat , is a red giant star and the second-brightest star (after Epsilon Pegasi) in the constellation of Pegasus. It forms the upper right corner of the Great Square of Pegasus, a prominent rectangular asterism. Nomenclature ''β Pegasi'' ( Latinised to ''Beta Pegasi'') is the star's Bayer designation. It bore the traditional name of ''Scheat'', a name that had also been used for Delta Aquarii. The name was derived from the Arabic ''Al Sā'id'' "the upper arm", or from ''Sa'd''. In 2016, the International Astronomical Union organised a Working Group on Star Names (WGSN) to catalog and standardise proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Scheat'' for this star (the name ''Skat'' was later approved for Delta Aquarii). In Chinese, (), meaning ''Encampment'', refers to an asterism consistin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Pegasi
Alpha Pegasi (α Pegasi, abbreviated Alpha Peg, α Peg), formally named Markab , is the third-brightest star in the constellation of Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. Properties Alpha Pegasi has a stellar classification of A0 IV, indicating that it is an A-type subgiant star that has exhausted the hydrogen at its core and has evolved beyond the main sequence. Its spectrum has also been classified as B9V and B9.5III. It is rotating rapidly, with a projected rotational velocity of 130 km/s giving a lower bound on the azimuthal velocity along the star's equator. The effective temperature of the photosphere is about 10,000 K and the star has expanded to nearly five times the radius of the Sun, emitting 165 times as much energy as the sun. Nomenclature ''α Pegasi'' ( Latinised to ''Alpha Pegasi'') is the star's Bayer designation. It bore the traditional name ''Markab'' (or ''Marchab''), which derived fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, 6. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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