Eddington limit

An upper limit on the ratio of the luminosity to mass of a stable star generating energy through the conversion of hydrogen to helium. Arthur S. Eddington (1881-1944) showed that the limit is 40,000 when units of the Sun's mass and luminosity are used. If the limit is exceeded, the outer layers of the star are blown away by radiation pressure and a planetary nebula is formed. The Eddington limit also sets an important constraint on the rate at which a black hole can grow by accreting matter.