The Accretion Rate in mass per unit time is used in calculations regarding Accretion Disks and other phenomena.
Accretion can result in heat as the release of the potential energy due to the gravitational force between the accreting matter and the body to which it is falling, which is called the Accretion Luminosity. A Maximum Accretion Rate can be calculated by assuming that Black Body radiation from the accretion-generated heat creates Radiation Pressure against the fall of the accreting matter, and assuming the phenomena is spherically symmetric and steady-state. Higher accretion (Super-Eddington Accretion) could be achieved if all these assumptions do not apply, and may explain some apparently very bright sources.
Active Galactic Nucleus (AGN)
Algol (Beta Per)
Cold Mass Accretion (CMA)
Core Accretion Model