In physics, the Eddington Limit is a natural limit to the luminosity that can be radiated by spherically symmetric accretion onto a compact object, like a black hole. It is named in honour of the British physicist Sir Arthur Eddington.

If luminosity exceeds the Eddington limit, there would be so much radiation pressure that the surrounding gas is pushed outward rather than inward. Without gas to provide energy, the luminosity naturally decreases to the Eddington limit where gas is pushed inward again.

The Eddington limit is a function of the mass of the accreting object:

where

• L_Eddington is the maximum luminosity that can be radiated by accretion.
• M is the mass of the compact object
• M_O is the Sun's mass.
• L_O is the Sun's luminosity.