Given by the Faber-Jackson and Tully-Fisher relations for galaxies, stars for which this property exceeds the Eddington limit will be unstable.
This property forms the basis of a classification scheme for active galactic nuclei developed by Fanaroff and Riley. One empirical law gives this property as a function of the velocity dispersion of an elliptical galaxy, while for spiral galaxies, it can be found from an empirical fit to the logarithm of the amplitude of maximum rotation. Given by the Faber-Jackson and Tully-Fisher relations for galaxies, stars for which this property exceeds the Eddington limit will be unstable. Two objects' relative magnitude is proportional to the logarithm of quotient of their values for this property, which can be found from the temperature and radius of an object via the Stefan-Boltzmann law. For 10 points, name this quantity located on the vertical axis on the Hertzsprung-Russell diagram, equivalent to an object's power output.
This property forms the basis of a classification scheme for active galactic nuclei developed by Fanaroff and Riley.
Luminosity 