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Highlights from the HEAO-1 Survey of Cataclysmic Variable Stars

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Frances C—rdova

California Institute of Technology, Pasadena, California 91125

Abstract

A survey of the x-ray properties of ~150 cataclysmic variable stars was conducted using the High Energy Astronomical Observatory, HEAO-1. U Geminorum was discovered to be emitting an intense soft x-ray flux and a weak hard x-ray flux during an optical outburst. Hard x-ray flickering was discovered from SS Cygni during optical quiescence. EX Hydrae and possibly AY Lyrae were detected in the soft x-ray while in their quiescent states. Most of the cataclysmic variables evidenced no x-ray emission, including ~20 dwarf novae which were observed by HEAO-1 during optical outbursts. Finally, soft x-ray pulsations were discovered from SS Cyg and U Gem. Simultaneous visual coverage was provided chiefly by the American Association of Variable Star Observers (AAVSO) and the Royal Astronomical Society of New Zealand Variable Star Section (VSS).