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P Cygni profile

(line profile showing both red and blue shifts)

A P Cygni profile is a spectral feature of some spectral lines, indicating they show both a redshift and a blue shift. This is a sign that some type of material is moving toward the observer, and some of the same type of material is moving away from the observer. The term is named for the star P Cygni which shows H-alpha emission lines with such a shape due to its stellar wind, with lines visible both from the wind coming toward Earth and that moving away from Earth.


Referenced by:
Palomar Four-filter Survey (PC)