A search for periodic and quasi-periodic photometric behavior in the cataclysmic variable TT Arietis

Observations of TT Ari obtained at 11 observatories (campaign TT Ari-94) du ring 258 hr were carried out to study optical variability on timescales fro m minutes to weeks. The best-fit primary photometric period determined from 16 nights of data obtained at the Dushak-Eregdag station of the Odessa Sta te University is P = 0.(d)133160 +/- 0.(d)000004 with a mean amplitude of 0 .0513 +/- 0.0008 mag. This new primary photometric period is larger than th at obtained during the TT Ari-88 campaign and is well outside the range of estimates published since 1961. Contrary to previous findings, the "5-7 hr" secondary photometric period is not seen. Our observations do show evidenc e for periods of 2.(d)916 and 0.(d)3040 with amplitudes of 43 and 25 mmag, respectively. The beat period between the spectroscopic and photometric per iods is not seen. No coherent oscillations in the range f = 10-2500 cycles day(-1) are found. The highest peaks in the power spectrum cover the wide r ange of 24-139 cycles day(-1). In the mean periodogram, the highest peak co rresponds to 21 and 30 minutes for the largest sets of observations, i.e., those obtained at Odessa and Krakow Universities, respectively. In the inst rumental B system, variations with an amplitude exceeding 0.011 mag occur 8 times (from 33 runs) at 24 minutes. We conclude that quasi-periodic variat ions occur at a few preferred timescales rather than at a relatively stable period with a secular decrease. In the frequency range 90-900 cycles day(- 1), the power spectrum obeys a power law with a slope ranging from gamma = 1.3 to 2.6 for different runs.