ULTRAVIOLET CONTINUUM VARIABILITY AND VISUAL FLICKERING IN THE PECULIAR OBJECT MWC-560

High-speed U-band photometry of the peculiar emission object MWC 560 o btained with the ground-based instrumentation, and V-band photometry o btained with the International Ultraviolet Explorer (IUE)-Fine Error S ensor (FES) indicates irregular brightness variations are quasi-period ic. Multiple peaks of relative brightness power indicate statistically significant quasi periods exist in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a prelimina ry model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudo-continuum absorption opacity in f ar-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cy g and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outbur st, occurring before they permanently enter the symbiotic nebular emis sion phase.