The bright inner part of the Sun's corona, caused by sunlight scattered from electrons. It is the true corona, as opposed to the F corona which is due to light scattered by dust particles. Owing to the extremely large speeds of the free electrons (averaging about 10 000 km/s for a coronal temperature of 2 million K), the Fraunhofer lines of the photospheric spectrum are smeared out so that the spectrum of the K corona is almost a pure continuum (the K stands for the German Kontinuum). The K corona is brighter than the F corona out to 1.5 solar radii from the Sun's surface.
Subjects: Astronomy and Astrophysics.