Quasi-Periodic Oscillations In the analysis of GK Per, a strange phenomenon can be observed¡Xquasi-periodic oscillations (QPO). ¡§QPOs are defined as low-coherence brightness oscillations thought to be associated with material within the inner accretion flows of CVs (Morales-Rueda, Still & Roche, hereafter MSR, 1999). Though the source can be considered periodic, its period has a certain variance. The state of the GK Per system affects the observed QPO period (PQPO) (Yi & Kenyon 1997). Various people have analyzed the …showed first 75 words of 1035 total…

…showed last 75 words of 1035 total…lines. When the blob passes through the first ¡¥threading region¡¦, a blue shift occurs; however, when it passes through the second, the signal is blocked by the inner accretion disk, so no red-shift is observed. As a result, the signal will be biased toward the blue (MSR 1999). With this model, both phenomena are taken into account, and no new models of QPO formation are required. Such evidence strongly suggests the validity of the beat-frequency model.