The clockworks of cataclysmic binary stars are rusting away. Most of the information about these stars comes to us courtesy of the periodicities they display, and some critical aspects of the physics rely on the accuracy with which these periods are known. Yet many observers have basically forsaken period-finding, driven perhaps by the scarcity of telescope time (since a period minimally requires watching a star do something for a few cycles). And there is no systematic effort to keep sufficient watch over these clocks to make sure that an ever-increasing time baseline is available to continue improving knowledge of the periods and their changes. Dr. Joseph Patterson, at Columbia University, has been developing the tools to make a strong impact on this situation. He has found a large fraction of certain classes of currently known cataclysmic binary stars and about 60% of recent orbital periods (through a network of collaborations). This includes precise orbital periods for two famous old cataclysmic variables (CVs), T Pyx and AM CVn, which have stubbornly guarded their secret from many decades of prior study, and which will now likely yield fundamental information on the direction and rate of binary evolution. Dr. Paterson will use this award to pursue tracing out a second main sequence of binaries with light secondaries driven out of thermal equilibrium, where angular momentum loss plays the role of nuclear burning familiar in single-star evolution. He has identified four of these period-bouncer stars, and he has learned how to find more. This is a major step towards learning how binary stars end their lives. Finally he will repeat a 1984 study of distances and accretion rates in CVs, for today's much-expanded roster. This will give improved values for the lifetime, space density, and scale height of CVs in the galaxy.
Over the last ten years Dr. Patterson and colleagues have assembled a worldwide network of small photometric telescopes, the CBA, able to study periodic phenomena with unprecedented thoroughness. This network of (mostly) amateur astronomers is now a major element in the research interface of amateur and professional astronomers, and, with proper nutrition, should flourish and expand beyond the realm of cataclysmic variables. This has been a happy symbiosis of the amateur's traditional interest in discovery with the physicist's traditional interest in experiments leading to confrontation with theory. ***
