Around 1930, S. Chandrasekhar studied astrophysical models of white dwarf stars and came to the conclusion that no white dwarf can be more massive than about 1.2 solar masses ()
This became known as the Chandrasekhar limit. Chandrasekhar was awarded the Nobel Prize for these studies, and went on to study stellar structure, resulting in the concept of black holes.

A simple treatment of the problem for a relativistic white dwarf gives

where is the mean number of nucleons per electron. For iron, which has the highest binding fraction, and

A more careful treatment gives (Weinberg 1972, p. 306). A more modern value is Shu (1982, p. 128) gives