Steady nuclear burning on white dwarfs

We investigate the steady nuclear burning of accreted hydrogen on a white dwarf. For a given CNO-abundance there is a maximum luminosity for which steady burning is possible. For normal solar abundances the maximum luminosity is $$\sim5\times10^{-2} L_\odot$$ corresponding to an accretion rate of $$\sim8\times10^{-13} M_\odot \text{yr}^{-1}$$. We argue that significant depletion of the CNO-abundance in the burning zone due to diffusion is unlikely.