A model for the intrinsic population of cataclysmic variables

Applying standard models of the formation and evolution of cataclysmic variables (CVs) we synthesize theoretically the present intrinsic CV population in a self-consistent way. This is done by combining published CV formation rates with a large number of evolutionary sequences covering all possible initial configurations. The influence of different assumptions entering the determination of the birth rate and of different prescriptions to compute magnetic braking is investigated quantitatively. As a main result we find that the detailed treatment of the common envelope phase has little influence, and that the most often cited prescriptions for magnetic braking give similar distributions. A theoretically predicted observable period histogram shows the principal effect of observational selection and proves that a pronounced "period gap" exists in the distribution of the total CV population when the disrupted magnetic braking model is applied to describe the evolution of individual CVs.