Fundamental Astronomy of Catalysmic Binaries

Dartmouth College, Hanover NH

Investigators

Abstract

AST 0307413 Thortensen, John R The cataclysmic variable stars are a broad class of close binary stars in which a white dwarf star gains mass from a cool main-sequence companion star. There are a rich range of phenomena associated with these stars and they constitute astrophysical laboratories in which to study accretion disks and binary stellar evolution. Exciting and important discoveries about cataclysmic variable stars rest on fundamental astronomical measurements. Here, a long-standing and very productive program of orbital period determinations through radial velocity measurements is being continued, encompassing a wide sample of cataclysmic variable stars. As part of this spectroscopic program, phase-resolved spectra of selected stars are being obtained to elucidate disk precession and gas flows, and to search for more examples of the anomalously warm secondary stars discovered just last year. A program of astrometry and direct imaging also is being continued, resulting in very accurate parallaxes and proper motions for a number of these objects. This firms up the distances and luminosities of cataclysmic variable stars and constrain their ages. The cumulative impact of this work on our understanding of cataclysmic binaries will be large. The broader impact of this work is largely through the opportunities it provides for student research. Undergraduate students are thrilled to participate in observing trips to Arizona; several students have gone on to become professional astronomers, in part because of this exposure. This grant supports a graduate student. The work also generates useful astronomical software, some of which has been spun off to the community.