Tolman-Oppenheimer-Volkoff equation

Tolman-Oppenheimer-Volkoff equation:

Factoring out a from the numerator and integrating the metric identity via substitution results in the Tolman-Oppenheimer-Volkoff equation.

If terms of order 1/c are neglected, the Tolman-Oppenheimer-Volkoff equation becomes the Newtonian hydrostatic equation, used to find the equilibrium structure of a spherically symmetric body of isotropic material when general-relativistic corrections are not important.