THE PERIOD DISTRIBUTION OF CATACLYSMIC BINARIES EVOLVING WITHOUT MAGNETIC BRAKING

We model a hypothetical subpopulation of cataclysmic binaries (CBs) wh ich are driven exclusively by orbital angular momentum losses due to g ravitational radiation, i.e. which do not experience magnetic braking. Applying the computational tools developed by de Kool (1992) and Kolb (1993) we synthesize the corresponding period histogram and compare i t to the observed period distribution of AM Her systems, for which ''n on magnetic braking'' models have been proposed recently. We find that for standard model assumptions such a subpopulation does not fit main features of the observed sample of AM Her stars.