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Lunar corona A solar corona up Beinn Mhòr (South Uist). In meteorology, a corona (plural coronae) is an optical phenomenon produced by the diffraction of sunlight or moonlight (or, occasionally, bright starlight or planetlight) [1] by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface.
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 ...
Coronagraph instruments are extreme examples of stray light rejection and precise photometry because the total brightness from the solar corona is less than one-millionth the brightness of the Sun. The apparent surface brightness is even fainter because, in addition to delivering less total light, the corona has a much greater apparent size ...
Coronal mass ejections are usually visible in white-light coronagraphs. A coronal mass ejection ( CME ) is a significant ejection of plasma mass from the Sun's corona into the heliosphere . CMEs are often associated with solar flares and other forms of solar activity , but a broadly accepted theoretical understanding of these relationships has ...
T Coronae Borealis (T CrB), nicknamed the Blaze Star, is a binary star and a recurrent nova about 3,000 light-years (920 pc) away in the constellation Corona Borealis. [9] It was first discovered in outburst in 1866 by John Birmingham, [10] though it had been observed earlier as a 10th magnitude star. [11]
Compared to the corona's usual closed magnetic field that arches between regions of opposite magnetic polarity, the open magnetic field of a coronal hole allows solar wind to escape into space at a much quicker rate. This results in decreased temperature and density of the plasma at the site of a coronal hole, as well as an increased speed in ...
In astronomy and in astrophysics, for radiative losses of the solar corona, it is meant the energy flux radiated from the external atmosphere of the Sun (traditionally divided into chromosphere, transition region and corona), and, in particular, the processes of production of the radiation coming from the solar corona and transition region, where the plasma is optically-thin.
Light curve of R Coronae Borealis from 1990 to 2017, showing the unprecedented deep minimum The variability of R Coronae Borealis was discovered by English astronomer Edward Pigott in 1795. [ 13 ] In 1935 it was the first star shown to have a different chemical composition to the Sun via spectral analysis .