A Preliminary Observational Search for Circumbinary Disks around Cataclysmic Variables

Abstract

Circumbinary (CB) disks have been proposed as a mechanism to extract orbital angular momentum from cataclysmic variables (CVs) during their evolution. As proposed by Taam & Spruit, these disks extend outward to several astronomical units and should be detected observationally via their infrared flux or by absorption lines in the ultraviolet spectra of the CV. We have made use of archival HST/STIS spectra, as well as our own near-IR imaging, to search for observational evidence of such CB disks in seven CVs. Based on the null result, we place an upper limit on the column density of the disk of N_H~10¹⁷cm^-2.

Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work was started while three of the authors (K. E. B., N. S., S. B. H.) were at the Planetary Science Institute, Tucson, AZ.