The Sun in the Light of Calcium Ions

The Sun in the Light of Calcium Ions

. This global spectroheliogram of the Sun was taken in the light of the singly ionized calcium, or Ca II, at the core of the violet K line with a wavelength of 393.4 nanometers on 02 June 1997. The emission outlines the chromospheric network where magnetic fields are concentrated, like the edges of the tiles in a mosaic. The brightest extended regions are called plage; they are dense places in the chromosphere found above sunspots or other active areas of the photosphere in regions of enhanced magnetic field. [Courtesy of the National Solar Observatory (NSO), the National Optical Astronomy Observatories (NOAO), and the National Science Foundation (NSF).]

Copyright 2010, Professor Kenneth R. Lang, Tufts University