Corona (optical phenomenon)

Last updated on 12 February 2017

In meteorology, a corona (plural coronae) is an optical phenomenon produced by the diffraction of light from the Sun or the Moon (or, occasionally, bright stars or planets)[1] by individual small water droplets and sometimes tiny ice crystals of a cloud or on a foggy glass surface. In its full form, a corona consists of several concentric, pastel-colored rings around the celestial object and a central bright area called aureole.[2][3] The aureole is often (especially in case of the Moon) the only visible part of the corona and has the appearance of a bluish-white disk which fades to reddish-brown towards the edge. The angular size of a corona depends on the diameters of the water droplets involved: Smaller droplets produce larger coronae. For the same reason, the corona is the most pronounced when the size of the droplets is most uniform. Coronae differ from halos in that the latter are formed by refraction (rather than diffraction) from comparatively large rather than small ice crystals.

Lunar-coronae.jpg
A lunar corona
Lunar corona.JPG
Lunar aureole as seen from Mumbai, India.
SolarDiffractionCorona.jpg
A solar corona soon after sunrise

See also

References

  1. ^ Cowley, Les (2012). "Jupiter corona from Iran". Atmospheric Optics. Retrieved 2016-05-02.
  2. ^ Calvert, J. B., The Corona, University of Denver, 2 August 2003. Access date 11 Feb. 2107
  3. ^ Cowley, Les, Corona, Atmospheric Optics. Access date 11 Feb. 2107

External links

Janus24.jpg
Lunar corona with Altocumulus floccus

Gallery

Coronae.jpg

Forest Corona

Solar coronae reflection.jpg

Reflection of solar corona

Coronae at GGB.jpg

Solar Corona at Golden Gate Bridge

Iridescent fog.jpg

Partial Corona at Golden Gate Bridge

Moon Marki 19032011 3.JPG

Lunar aureole

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