Abstract
We obtaln numerical fits for the limit mass (newtonian), maximum gravitational mass (relativistic), and binding energy for several sequences of white dwarfs of different chemical compositions. We calculate the value of the average adiabatic index for each model. The critical value of this index is larger than the classical value of 4/3; this implies, for example, that for carbon dwarfs the relativistic instability appears at 1.3430. This results is confirmed by the hydrodynamical calculations.
