AAVSO: American Association of Variable Star Observers

Time Series Observations of IP Pegasi Using an Inexpensive Ambient Temperature CCD Camera (Abstract)

Volume 36 number 2 (2008)

George H. Keel
Keith A. Graham
Donald F. Collins


(Abstract only) IP Pegasi is an eclipsing cataclysmic variable star. The system occasionally goes into outburst due to accretion disk instabilities. Observations at quiescence were collected with a 20-cm aperture Schmidt Cassegrain Telescope. The images were recorded with a Meade DSI-Pro CCD camera. Co-adding was required to eliminate noise due to the ambient temperature CCD detector. The observations were unfiltered. AAVSO V-filtered and unfiltered observations were obtained during outburst. One objective of this study was to obtain time series photometric data from the low cost camera. This camera successfully provided unfiltered light curves of cataclysmic variable stars. A second objective was to analyze light curves of IP Pegasi and determine a probable structure of the system. The light curve during outburst displays a high luminosity midway between narrow eclipses. During quiescence, the peak intensity occurs just before the eclipse begins, and the eclipse is not symmetrical. The light curves support the belief that during outburst the brightest region lies in the vicinity of the white dwarf. During the quiescent state, the brightest regions of the system appear to be distributed among the red dwarf, the white dwarf, and the hot spot on the perimeter of the accretion disk. This study was funded by the American Astronomical Society, Small Projects Grant. It was also funded by the North Carolina Academy of Sciences, Yarbrough Grant.