High-speed multicolor photometry of V834 Centaurus

Results are presented of high-speed photometric observations of the Am Her object, V834 Centaurus which, during its high state, revealed the 0.3-0.9 Hz quasi-period oscillations (QPOs) with rms amplitudes of 3.3 +/-1.1 percent and 2.5 +/-0.8 percent in the V and R bands, respectively, while the U-band amplitude was consistent with zero on one night but was 2.5 +/-1.2 percent on the following night. The QPOs in the B band were always consistent with zero. The data were obtained on the nights of June 16-21, 1990, when the average V magnitude of V834 Cen was about 15.3, confirming the high-luminosity state. The dominance of the QPOs by V-band emission is in contrast to earlier studies by Larsson which found that the QPOs were dominated by emission in the B and R band, depending upon the luminosity state of V834 Cen. In all cases, the QPOs of V834 have frequencies of 0.3-0.9 Hz. It is inferred that the color of the QPOs could be highly variable between luminosity states and may be variable in the U band within the high-luminosity state.