Subrahmanyan Chandrasekhar
1910 – 1995 · India
Known for: Theoretical astrophysicist who derived the Chandrasekhar limit for white dwarf stars
“He found the limit beyond which a star can no longer hold itself up.”
Biography
Subrahmanyan Chandrasekhar was born in Lahore in 1910, in British India, into a Tamil family; his father was a railway auditor and his mother, who had translated Ibsen's A Doll's House into Tamil, drew out his curiosity early. The household moved to Madras in 1918. Tutored at home until he was twelve, he read physics at Presidency College and published his first paper, on Compton scattering and the new quantum statistics, in 1929. A government scholarship, arranged with the help of Ralph Fowler, took him to Trinity College, Cambridge, in 1930; his uncle C. V. Raman won the Nobel Prize in Physics that same year.
On the voyage to England he worked out the statistical mechanics of the degenerate electron gas that holds a white dwarf up against its own weight, including the relativistic increase of electron mass that Fowler's treatment had left out. The calculation produced a ceiling, about 1.44 solar masses, above which a stellar remnant must collapse further, into what is now called a neutron star or a black hole. Arthur Eddington criticised the result publicly in 1935, and years passed before it was accepted as the basis of modern accounts of how massive stars end. After a Cambridge doctorate and a Trinity prize fellowship, Chandrasekhar joined the University of Chicago in 1937 and remained there for the rest of his life, working for a period at Yerkes Observatory and editing The Astrophysical Journal from 1952 to 1971.
He worked in long campaigns, giving years at a time to stellar dynamics, where he described the effect he called dynamical friction, then to radiative transfer, hydrodynamic and hydromagnetic stability, the equilibrium of ellipsoidal figures, and finally the mathematical theory of black holes and colliding gravitational waves, closing each subject with a monograph. The Nobel Prize in Physics came in 1983, half a century after the work that first made his name. His last book was a study of Newton's Principia written for the general reader, published in the year he died, 21 August 1995, in Chicago, at the age of 84. NASA's Chandra X-ray Observatory carries his name, as does the mass limit that first brought it to notice.