The Magnetic Nature of the Cataclysmic Variable Period Gap

One of the most important problems in the context of cataclysmic variables (CVs) is the lack of observations of systems with periods between 2 and 3.12 hr, known as the period gap. The orbital evolution of CVs with periods shorter than those in the gap is dominated by gravitational radiation, while for periods exceeding those of the gap it is dominated by magnetic braking of the secondary star. Spruit & Ritter showed that as periods approach 3 …