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Paper: HST IUE UV variability in FO AQR
Volume: 157, Annapolis Workshop on Magnetic Cataclysmic Variables
Page: 41
Authors: de Martino, D.; Silvotti, R.; Mouchet, M.; Mukai, K.; Buckley, D. A. H.; Gänsicke, B. T.; Rosen, S.
Abstract: A study of the characteristics of the UV periodicities in FO Aqr is presented. A strong orbital modulation dominates both UV continuum and emission line fluxes, while the V/R ratios of the main UV lines vary only at the rotational frequency. The dominance of the orbital periodicity is also observed in coordinated optical photometry, while previously FO Aqr has always been found to be spin dominated. A spectral analysis of the variabilities shows no basic change in the effects of X-ray illumination, but does show a decrease in size of the accretion curtain together with an increase of the thickened part of the accretion disk (the bulge). These observations indicate that FO Aqr switched into a disk-overflow state on a timescale of five years.
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