mass-luminosity relation

(astrophysics) A relation between stellar magnitudes and mass of the stars; when the absolute magnitudes of stars are plotted versus the logarithms of their masses, the points fall closely along a smooth curve.

The relation, observed or predicted by theory, between the quantity of matter a star contains (its mass) and the amount of energy generated in its interior (its luminosity). Because of the great sensitivity of the rate of energy production in a stellar interior to the mass of the star, the mass-luminosity relation provides an important test of theories of stellar interiors.

For a family of stars with different masses but with the same mixture of chemical elements uniformly distributed throughout the stellar volumes, there will be a unique mass-luminosity relation. Since most of the stars in the solar neighborhood have about the same chemical composition, the observed relation, obtained from binary stars for which masses and luminosities can be observationally evaluated, conforms reasonably well with theory. See also Binary star; Star.