Spectroscopic and photometric behaviour of the class of recurrent novae with
giant secondaries (T Coronae Borealis, RS Ophiuchi, V3890 Sagittarii and V745
Scorpii) at quiescence are presented in this study. The hot component in these
systems is variable, with the variability manifesting as variability in the
ultraviolet luminosity, the ultraviolet and optical emission line fluxes and in
the UBV/visual magnitudes. The variations are uncorrelated with the binary
orbital motion. The observed ultraviolet+optical spectral characteristics of
the hot component in these systems can be explained by a white dwarf+accretion
disc embedded in an envelope of wind from the M giant secondary. We suggest the
observed variations are a result of (a) fluctuations in the mass accretion
rate; (b) changes in the column density of the absorbing, optically thick, wind
envelope.Comment: 11 pages, 7 postscript figures. Uses laa.sty, eps.sty. To appear in
A&A (main journal
