Radiative efficiency for different α_* as a function of the disk’s inner radius, given in terms of the R_ISCO. The total disk luminosity is calculated using the Artemova (A96; solid black lines) and the Mukhopadhyay (M02; solid orange lines) potentials. The dotted black lines correspond to Eq. (14), while the orange ones fit a similar expression with a power-law index of p = 0.75.