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Paper: Third component in cataclysmic variables: Additional mechanism for accretion rate changes?
Volume: 261, The Physics of Cataclysmic Variables and Related Objects
Page: 47
Authors: Andronov, I. L.; Chinarova, L. L.
Abstract: An additional mechanism for variability of the characteristics of cataclysmic variables owed to accretion rate changes is discussed. Small variations of the distance between the components owed to the presence of a third body -- brown dwarf or a giant planet -- may cause much larger response amplified by a strong dependence of the accretion rate on the radius excess of the Roche lobe-filling secondary as well as by the irradiation. This mechanism makes accretion rate variations more complicated as compared with the models of solar-type activity of the secondary. One of the proposed candidates is EM Cyg, where a 3000-day cyclicity was found (Chinarova & Andronov 1996). A contribution of the red dwarf third body was detected in the emission from EM Cyg by North et al. (2001), but it is not clear, whether this star is physically related to the cataclysmic binary. Variations of the outburst cycle length are also seen in X Leo, AB Dra, IR Gem, AY Lyr, LL Lyr and some other stars. Another candidate is V792 Cyg, where a switch of the seasonal mean outburst cycle from 25--29d to ≅39d was detected (Chinarova & Andronov 2000).
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