QPO
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 optical periodicity, but their results vary greatly. For example, Patterson (1981) observed the source during quiescence in 1978, finding PQPO to be about 380 seconds. During the decline phase of GK Per in 1983, Mazeh et al. (1985) found PQPO ~360 sec, and also determined PQPO ~400 s during two nights of GK Per¡¦s outburst phase (Yi & Kenyon 1997). Watson, King & Osborne (1985) also observed a ~5000 s QPO through the analysis of X-ray data. No consensus has been reached as to a single model for the QPO phenomenon. Theoretical models suggest dense blobs in orbit within the inner disk (Bath 1973), pulsations on the surface of the white dwarf (Papaloizou & Pringle 1978), or oscillating a
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Some common words found in the essay are:
Cowley Fisher, King Osbourne, Yi Kenyon, Papaloizou Pringle, Hellier Livio, King Osborne, Quasi-Periodic Oscillations, Morales-Rueda Roche, Observatory October, La Palma, accretion disk, msr 1999, emission spectra, lomb-scargle algorithm power, double peaks, kenyon 1997, biased blue, algorithm power, lomb-scargle algorithm, observations msr, watson king, yi kenyon 1997,
Approximate Word count = 1017
Approximate Pages = 4 (250 words per page double spaced)
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