H-Accreting CO WDs: Accretion Regimes and Final Outcomes.

The long term evolution of Carbon-Oxygen White Dwarfs accreting Hydrogen rich matter at a rate typical for a recurrent mild H-flashes regime is reviewed to determine the dependence of the various accretion regimes on both the accretion rate and the chemical composition of the accreted matter. On the basis of these results semi-analytical relations defining the steady state regime are provided for different values of the metallicity in the accreted matter. In addition it has been found that models accreting H-rich matter in a pulsating regime can undergo an explosive dynamical He-ignition in the He-buffer accreted as a by-product of the overlying H-burning shell. [ABSTRACT FROM AUTHOR]