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We have investigated properties of the Quasi Periodic Oscillation (QPO)features in the accretion powered X-ray pulsar Cen X-3 over a period of aboutfour years using observations carried out with the Proportional Counter Array(PCA) of the {\it {Rossi X-ray Timing Explorer}}. The observations cover a widerange of X-ray intensity of the source in excess of the binary intensitymodulation. We have detected QPOs in 11 out of a total 81 pointings with thePCA with rms intensity fluctuation upto 10%. The QPO peak frequency showsclustering around 40 and 90 mHz with the QPO frequency having no dependence onX-ray intensity. This indicates that either (a) the observed X-ray luminosityof the source is not related to the mass accretion rate or inner radius of theaccretion disk or (b) that the QPO generation mechanism in Cen X-3 is differentfrom the beat frequency model or Keplerian frequency model that is believed tobe operational in most other transient and persistent X-ray pulsars. We havealso found that, the rms variation in the 40 mHz QPO feature is not dependenton the X-ray energy, indicating that disk absorption related origin for the QPOis unlikely.

Quasiperiodic oscillations in Cen X-3 and the long term intensity variations