An Etymological Dictionary of Astronomy and Astrophysics
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The theoretical upper limit of → luminosity at which the → radiation pressure of a light-emitting body would exceed the body's → gravitational attraction. A star emitting radiation at greater than the Eddington limit would break up. The Eddington luminosity for a non-rotating star is expressed as: L_Edd = 4πGMm_pcσ_T^-1, where G is the → gravitational constant, M the star mass, m_p the → proton mass, c the → speed of light, and σ_T the → Thomson cross section. It can also be written as L_Edd = 4πGMcκ^-1, where κ is the → opacity. In terms of solar mass, the Eddington limit can be expressed by: L_Edd = 1.26 × 10³⁸ (M/Msun) erg s^-1. See also → rotational Eddington limit.

Named after Arthur Stanley Eddington (1882-1944), prominent British astrophysicist; → limit.

The → Eddington limit of luminosity for a → rotating star in which both the effects of → radiative acceleration and rotation are important. Such objects mainly include → OB stars, → LBV, → supergiants, and → Wolf-Rayet stars. It turns out that the maximum permitted luminosity of a star is reduced by rotation, with respect to the usual Eddington limit (Maeder & Meynet, 2000, A&A, 361, 159).

→ rotational; → Eddington limit.