Corona

A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. The word "corona" itself derived from the Latin, meaning crown, which in turn came from the Ancient Greek κορώνη (korōnē) meaning "garland" or "wreath".

The high temperature of the corona gives it unusual spectral features, which led some to suggest, in the 19th century, that it contained a previously unknown element, "coronium". These spectral features have since been traced to highly ionized iron (Fe-XIV) which indicates a plasma temperature in excess of 106 kelvin. The fact that the Sun has a million-degree corona was first discovered by Gotrian in 1939 and Bengt Edlén in 1941 by identifying the coronal lines (observed since 1869) as transitions from low-lying metastable levels of the ground configuration of highly ionized metals (the green FeXIV line at 5303 Å, but also the red line FeX at 6374 Å).

Light from the corona comes from three primary sources, which are called by different names although all of them share the same volume of space. The K-corona (K for kontinuierlich, "continuous" in German) is created by sunlight scattering off free electrons; Doppler broadening of the reflected photospheric absorption lines completely obscures them, giving the spectral appearance of a continuum with no absorption lines. The F-corona (F for Fraunhofer) is created by sunlight bouncing off dust particles, and is observable because its light contains the Fraunhofer absorption lines that are seen in raw sunlight; the F-corona extends to very high elongation angles from the Sun, where it is called the zodiacal light. The E-corona (E for emission) is due to spectral emission lines produced by ions that are present in the coronal plasma; it may be observed in broad or forbidden or hot spectral emission lines and is the main source of information about the corona's composition.

Read more about Corona:  Physical Features, Variability of The Corona, Stellar Coronae, Physics of The Corona, Coronal Heating Problem

Other articles related to "corona":

Corona, Queens - Notable Residents
... Notable current and former residents of Corona include Cannonball Adderley (1928–1975), jazz alto saxophonist Nat Adderley (1931–2000), jazz cornet and trumpet player Louis Armstrong (1901 ... the 1960s, and later founder of the Algebra Project, lived at 108-63 Ditmars Boulevard in Corona Carlos D ... Hip-hop musicians from Corona The Beatnuts Kid 'n Play Kool G Rap (born 1968), rapper ...
Corona Stage Academy
... Corona Stage Academy, also known as The Corona Stage School, was a successful British drama school founded by Miss Rona Knight in the mid-1940s ...
Lac Minerals Ltd. V. International Corona Resources Ltd. - The Issues
... the Supreme Court of Canada did a fiduciary relationship exist between Corona and Lac which was breached by Lac's acquisition of the property? did Lac misuse confidential information obtained ...
Lac Minerals Ltd. V. International Corona Resources Ltd. - Decision of The Supreme Court of Canada
... a constructive trust on Lac in favour of Corona was the appropriate remedy ... relationship Yes No ongoing relationship, but a fiduciary duty arose when Corona made confidential information available to Lac with respect to the ... Imposition of a constructive trust on Lac in favour of Corona with respect to the property ...
Lac Minerals Ltd. V. International Corona Resources Ltd. - The Facts
... International Corona was a junior mining company that was investigating the mineral potential of a property at Hemlo in Northern Ontario ... Lac Minerals, a senior mining company, heard of Corona's activity and arranged to visit the site ... Corona showed Lac's representatives detailed information about their geological findings, together with their underlying theory about its mineral potential and importance ...