A simple model of the outer layers of a star, used in studying the formation of absorption lines in stellar spectra. It assumes that absorption occurs throughout the outer region of the star, rather than in just the cool outermost layers, and that the ratio of line absorption to continuum absorption is constant. It successfully predicts the strength of lines of ionized metals such as calcium and iron in solar-type and similar stars. The model is named after E. A. Milne and A. S. Eddington.
Subjects: Astronomy and Astrophysics.