Gravitational radiation and the evolution of cataclysmic binaries

Model evolutionary computations were done for a low-mass secondary component filling its Roche lobe. Mass transfer from the secondary onto a primary component was driven by angular momentum loss caused by gravitational radiation. The secondary was initially a lower-main-sequence star, and it gradually became degenerate as a result of mass loss. The orbital period initially decreased to a minimum value close to 80 minutes and then increased. The observed hydrogen-rich cataclysmic binaries have a short-period cutoff at 81 minutes. This indicates that gravitational radiation is the main driving force for the evolution of such short-period systems.