Sir James Jeans and the Stability of Gaseous Stars

Abstract

In 1925 Sir James Jeans calculated that a star made up of an ideal gas, generating energy as a moderately positive function of temperature and density, could not exist. Such stars would be unstable to oscillations of increasing size. It appears that the flaw in his calculation has never been clearly explained, especially the physical basis for it. I conclude it lies in an almost offhand assumption made about the form of the temperature perturbation. The episode has lessons concerning the structure of stars, the use of perturbation methods (especially in discussing stability), the use of mathematical models and the process by which one theory is chosen over its competitors.