stellar corona

A corona (pl. coronas or coronae) is the outermost layer of a star's atmosphere. It consists of plasma.

The Sun's corona lies above the chromosphere and extends millions of kilometres into outer space. It is most easily seen during a total solar eclipse, but it is also observable with a coronagraph. Spectroscopic measurements indicate strong ionization in the corona and a plasma temperature in excess of 1000000 kelvins,1 much hotter than the surface of the Sun, known as the photosphere.

It is an X-ray emitter with its stellar corona giving off an X-ray luminosity of.