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corona
corona
1. An extremely hot (about 2 million K), highly ionized gas surrounding the Sun. Certain other stars also have coronae. The Sun's corona is visible at total eclipses as a white region extending out to several solar radii, displaying streamers, plumes, and bubbles or loops. The radiation of the white-light corona has components due to emission lines (the E corona), and scattering from electrons (the K corona) and dust particles (the F corona). The corona's outer extension is the solar wind. X-ray images of the Sun's corona show complex loop structures near sunspot groups, and near smaller X-ray bright points. The X-ray emission, plus emission lines due to highly ionized atoms (coronal lines), shows that the temperature is about 2 million K; even higher temperature of 4 million K or more are found in active regions. Magnetic fields, with a strength of about 10−3 tesla, govern the corona's shape. The magnetic fields form closed loops in active regions and much of the quiet corona (i.e. non-active regions), but in coronal holes the magnetic field lines are open and stretch out into space, not returning to the Sun. The energy that heats the corona is thought to come from motions in and below the solar photosphere. High‐frequency photospheric motions create waves in the Sun's magnetic field that travel outwards into the corona. Conversion of the wave energy into heat can account for the high temperatures of the coronal gas. One method of dissipating the wave energy is if the wave resonates with the coronal gas. An alternative heating mechanism requires low‐frequency photospheric motions to tangle up the magnetic lines of force in the corona. Eventually the stresses in the magnetic field are released through reconnection of field lines. The energy released in such events is expected to vary widely, from flares to so‐called microflares and even smaller nanoflares. The appearance of the corona changes during the solar cycle. At solar maximum it consists of many active-region loops and streamers around the disk, but at solar minimum it is dominated by large coronal holes at each pole and a sheet-like structure near the equator. Main-sequence stars cooler than spectral type F0 often have coronae with active regions, as indicated by their X-ray emission. This is particularly true of the M-type dwarf flare stars. Coronae are also present in some interacting binary systems like the RS Canum Venaticorum stars. 2. A large circular or elongated feature on a planetary surface, surrounded by concentric ridges; pl.coronae. The name, which means ‘crown’ or ‘circle’, is not a geological term, but is used in the nomenclature of individual features, for example Nightingale Corona on Venus, or Arden Corona on Uranus's satellite Miranda. 3. A region of tenuous, very hot gas extending out of the galactic plane in spiral galaxies such as the Milky Way; also called galactic corona. |
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"corona." A Dictionary of Astronomy. 1997. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." A Dictionary of Astronomy. 1997. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O80-corona.html "corona." A Dictionary of Astronomy. 1997. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-corona.html |
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corona
corona
1. Coloured rings of lights, typically from blue inside to red outside, that sometimes appear to surround the Sun or Moon. The effect is created by diffraction of light by spherical water drops in such clouds as altocumulus. Compare HALO. 2. Concentric zones of one or more minerals surrounding a core mineral. Coronas can be formed in a number of ways. (a) The discontinuous reaction of minerals with a magma can be preserved as coronas around the original high-temperature mineral if the cooling rate is fast enough to prevent the reactions going to completion. (b) Late-stage fluids may react with an earlier primary mineral to develop a corona of secondary minerals. (c) Two minerals may undergo sub-solidus reactions (reactions occurring after the rock has solidified) to maintain equilibrium as a rock mass cools, developing a corona of lower-temperature minerals. These types of texture are also known as ‘reaction rims’. See also CRYSTAL ZONING. 3. One of the large, circular features (150–600km diameter) of uncertain origin, comprised of up to 10–12 subconcentric ridges and grooves, which surround an inner region of irregular relief, found on the surface of Venus, mainly in a latitudinal belt 55° N–80° N along the borders of Ishtar and Tethus Regio. Most are associated with what appear to be lava flows. |
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AILSA ALLABY and MICHAEL ALLABY. "corona." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "corona." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O13-corona.html AILSA ALLABY and MICHAEL ALLABY. "corona." A Dictionary of Earth Sciences. 1999. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-corona.html |
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corona
co·ro·na1 / kəˈrōnə/ • n. (pl. -nae / -nē; -nī/ ) 1. Astron. the rarefied gaseous envelope of the sun and other stars. ∎ (also corona discharge) Physics the glow around a conductor at high potential. ∎ a small circle of light seen around the sun or moon, due to diffraction by water droplets. 2. Anat. a crown or crownlike structure. ∎ Bot. the cup-shaped or trumpet-shaped outgrowth at the center of a daffodil or narcissus flower. 3. a circular chandelier in a church. 4. Archit. a part of a cornice having a broad vertical face. co·ro·na2 • n. a long, straight-sided cigar. |
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"corona." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-corona005.html "corona." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-corona005.html |
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corona
corona (pl. coronae).
1. Part of a Classical cornice, called larmier, above the bedmoulding and below the cymatium, with a broad vertical face, usually of considerable projection, with its underside recessed and forming a drip protecting the frieze under it. 2. Circlet or hoop hanging from above, as over an altar: usually carrying candles, it is called a corona lucis, a good example of which survives in Aachen Cathedral. |
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JAMES STEVENS CURL. "corona." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. JAMES STEVENS CURL. "corona." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O1-corona.html JAMES STEVENS CURL. "corona." A Dictionary of Architecture and Landscape Architecture. 2000. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O1-corona.html |
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Corona
Corona , city (1990 pop. 76,095), Riverside co., S Calif.; inc. 1896. The city developed as a primary citrus fruit producer and shipping center. There is also light manufacturing. The name Corona ( "circle" ) was derived from the 3 mi (5 km) circular drive around the city that was once used for car racing. State prisons for men and women are nearby. Cleveland National Forest and hot springs lie in the vicinity. |
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"Corona." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "Corona." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-Corona.html "Corona." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-Corona.html |
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corona
corona luminous envelope surrounding the sun , outside the chromosphere. Its density is less than one billionth that of the earth's atmosphere. The corona is visible only at the time of totality during a total eclipse of the sun. It then appears as a halo of light with an irregular outer edge, often with streamers radiating from the sun's surface and contrasting with the dark lunar disk that it borders. It is divided into the inner corona, a ring of pale-yellow light against which crimson prominences are outlined, and the outer corona, a pearly white halo that extends far out into space. The corona consists of ionized gas at a temperature of 1 million°C. By means of the coronagraph , the innermost part of the corona can be studied and photographed in full daylight. Although the visible corona extends a few solar radii above the sun, because of its high temperature it produces a continual flow of electrically charged particles called the solar wind that move outward through the solar system. |
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"corona." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-corona.html "corona." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-corona.html |
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corona
corona Coloured rings of lights, typically from blue inside to red outside, which sometimes appear to surround the Sun or Moon. The effect is created by the diffraction of light by spherical water drops in such clouds as altocumulus. Compare halo.
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MICHAEL ALLABY. "corona." A Dictionary of Ecology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "corona." A Dictionary of Ecology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O14-corona.html MICHAEL ALLABY. "corona." A Dictionary of Ecology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-corona.html |
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corona
corona Outermost layer of the Sun's atmosphere, extending for many millions of kilometres into space. The corona emits strongly in the X-ray region, and has been studied by X-ray satellites. The corona has a temperature of 1–2 million K.
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"corona." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-corona.html "corona." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-corona.html |
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Corona
Corona ♀ (German) From a Late Latin name meaning ‘crown’; name of a minor saint martyred in Syria in the 2nd century, who was venerated in Bavaria, Austria, and Bohemia in the Middle Ages.
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PATRICK HANKS, KATE HARDCASTLE, and FLAVIA HODGES. "Corona." A Dictionary of First Names. 2006. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. PATRICK HANKS, KATE HARDCASTLE, and FLAVIA HODGES. "Corona." A Dictionary of First Names. 2006. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O41-Corona.html PATRICK HANKS, KATE HARDCASTLE, and FLAVIA HODGES. "Corona." A Dictionary of First Names. 2006. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O41-Corona.html |
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Corona
Corona, California/USA South Riverside Renamed in 1896 from the Spanish corona ‘crown’ or in this case ‘circle’ for the circular circuit which was sometimes used for motor racing.
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JOHN EVERETT-HEATH. "Corona." Concise Dictionary of World Place-Names. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. JOHN EVERETT-HEATH. "Corona." Concise Dictionary of World Place-Names. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O209-Corona.html JOHN EVERETT-HEATH. "Corona." Concise Dictionary of World Place-Names. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O209-Corona.html |
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corona
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MICHAEL ALLABY. "corona." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "corona." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O7-corona.html MICHAEL ALLABY. "corona." A Dictionary of Plant Sciences. 1998. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-corona.html |
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corona
corona (kŏ-roh-nă) n. a crown or crownlike structure. c. capitis the crown of the head.
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"corona." A Dictionary of Nursing. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." A Dictionary of Nursing. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O62-corona.html "corona." A Dictionary of Nursing. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-corona.html |
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corona
corona member of a cornice XVI; circle or halo of light XVII. — L., CROWN.
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T. F. HOAD. "corona." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "corona." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O27-corona.html T. F. HOAD. "corona." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-corona.html |
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corona
corona
•belladonna, Connor, donna, goner, gonna, honour (US honor), Maradona, Mashona, O'Connor, Shona, wanna
•corner, fauna, forewarner, Lorna, Morna, mourner, sauna, scorner, suborner, warner
•softener • Faulkner
•downer, uptowner
•sundowner
•Arizona, Barcelona, boner, condoner, corona, Cremona, Desdemona, donor, Fiona, groaner, Iona, Jonah, kroner, Leona, loaner, loner, moaner, Mona, owner, Pamplona, persona, postponer, Ramona, stoner, toner, Valona, Verona, Winona
•landowner • homeowner • shipowner
•coiner, joiner, purloiner
•crooner, harpooner, lacuna, lacunar, lampooner, Luna, lunar, mizuna, Oona, oppugner, Poona, pruner, puna, schooner, spooner, Tristan da Cunha, tuna, tuner, Una, vicuña, yokozuna
•honeymooner • Sunna • Brookner
•koruna
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"corona." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "corona." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O233-corona.html "corona." Oxford Dictionary of Rhymes. 2007. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-corona.html |
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