Placing Chandra’s work in historical context

In their engaging recollections of Subrahmanyan Chandrasekhar’s extraordinary career, neither Freeman Dyson nor Kamesh Wali mention that Chandra was the third person, not the first, to publish a white dwarf mass limit that involved a relativistic treatment of degenerate electrons. Chandra himself would have agreed that he was not the first, since he cites Edmund Stoner, ¹ who, in turn, was inspired by the work of Wilhelm Anderson, ² who also incorporated special relativity into a white dwarf mass limit. In his book on stellar structure, ³ Chandra also mentions Anderson and Stoner on page 422 and in his note 6 on page 451.

So what did Chandra do that was new? Both Anderson and Stoner found their mass limits for a uniform-density star and thus a star whose basic density profile was not derived from a proper treatment of hydrostatic equilibrium. Chandra subsequently calculated the mass limit using a polytropic equation of state, ⁴ which did incorporate hydrostatic equilibrium and was known at the time to produce a better approximation to stellar radial density profiles. Chandra’s polytrope mass limit is less than Stoner’s uniform-density mass limit by about 20%. Incidentally, Stoner, along with Frank Tyler, also later published a polytrope generalization. ⁵

In short, the white dwarf mass limit widely attributed to Chandra should really be the specific mass limit calculated for a polytrope. The conceptual breakthrough—that a relativistic treatment of degeneracy leads to the existence of a mass limit—was already identified by Stoner and Anderson. Dyson and Wali appear to misattribute this initial conceptual breakthrough to Chandra.