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ionization front





Pelican Nebula ionization front
The light from young energetic stars is slowly transforming the Pelican Nebula's cold gas to hot gas, with the advancing boundary between the two being marked by an ionization front. Most of these bright stars lie off the top of the image, but part of the bright ionization front crosses on the upper right.
A transition region where interstellar gas changes from a mostly neutral state to a mostly ionized state. Ionization fronts are typically found in the vicinity of hot stars and define the extent to which stellar ultraviolet has ionized the material around them.


Related category

   • INTERSTELLAR AND INTERPLANETARY MATTER