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PREDNASAJUCI / LECTURER :
Ivan L. Andronov

Odessa National Maritime University

NAZOV / TITLE :
Multiple timescales in the Nova-Like Cataclysmic Variable TT Ari 

ABSTRAKT / ABSTRACT :

We present results of several observational campaigns of TT Ari, one of the most
 puzzling cataclysmic variables - starting from 1992 to November, 2009.
The object shows a wide variety of processes which occur at different time-scales
 from 8 seconds to billion years.
It is usually at a "permanent outburst" (~11 mag), but shows "excursions" to a
 faint state of ~17 mag (in 1982 and in October-November, 2009; sometimes the
 photometric waves - superhumps - have a longer period, than the orbital one
 (positive superhamps); sometimes -shorter (negative superhums); during a negative
 superhump state, there are characteristic 15-25 min quasi-periodic oscillations,
 contrary to a positive superhump state, when the QPOs are practically absent;
 There is a strong dependency of the color index on the characteristic timescale -
 i.e. the QPOs have "bluer" spectral energy distribution than the superhumps and
 the mean flux; it was suggested that the superhump state depends on luminosity -
 however, there is evidence on the system's "memory" on the luminosity states.

Obsevational results are interpreted in terms of modern theories of precession of
 the accretion disk in the cataclysmic variables.