Related topics: sun

ESA's solar eclipse maker, Proba-3

Hundreds of millions of people will witness next week's total solar eclipse across North America, and solar physicists from around the globe are flocking to join them. Eclipses offer a brief glimpse of the sun's ghostly surrounding ...

Scientists pursue the total solar eclipse with NASA jet planes

The April 8, 2024, total solar eclipse will produce stunning views across North America. While anyone along the eclipse path with a clear sky will see the spectacular event, the best view might be 50,000 feet in the air, ...

Totality ready: US braces for April 8 solar eclipse frenzy

US communities along the path of the April 8 total solar eclipse are preparing for the year's biggest astronomic event, with millions of visitors expected to brighten local economies—and snarl up logistics.

Protein CENP-E plays important role during cell division

Cells divide to produce new cells. A protein meshwork called the fibrous corona plays an important role during this process, as it ensures that DNA is evenly distributed over the new daughter cells. In collaboration with ...

page 1 from 14


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 Latin root of the word corona means crown.

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.

This text uses material from Wikipedia, licensed under CC BY-SA