Radiative efficiency ($\eta =L/(\dot{M}{c}^2)$)

The radiative efficiency is the escaping radiative power divided by an adopted accreted rest-mass energy rate. Its meaning depends on where the mass rate is measured and which emission is counted. For efficient Newtonian accretion onto a stellar surface it scales as $GM/(R_{\ast }{c}^2)$, whereas advection or outflows can reduce luminosity for the same supplied mass.