Galactik Model Parameters of Cataclysmic Variables In this thesis, using 2MASS and WISE photometric data and the cataclysmic variables with 82,4 ≤ P (min) ≤ 720 selected from the catalogue of Ritter and Kolb (2003), orbital period- luminosity-colours (PLC) relations and Galactic model parameters of the systems are investigated. PLC relation estimated from 25 cataclysmic variables with well known parallaxes is based on orbital periods, (J – Ks) and (Ks – W1) colours. This new absolute magnitude calibration gives ~2 times better results and can be used to construct statistically reliable data sets in order to estimate distances of cataclysmic variables. Using this absolute magnitude calibration, distances of 263 cataclysmic variables with 10 ≤ J0 ≤ 16 are estimated. These distances were used to estimate exp, sech and sech2 distributions of the vertical distances from the Galactic plane. These distributions were used to estimate the scale height of 218 pc for cataclysmic variables. With the same sample, space density of the cataclysmic variables in the Solar neighbourhood was found 5 10-6 pc-3. Although this space density is in agreement with the observational results in the literature, it is ~2.5 factor smaller than the theoretically predicted values. In addition, luminosity functions of cataclysmic variables were determined, as well. Luminosity functions of cataclysmic variables increases to fainter magnitudes, while they tend to be flatter beyond MJ = 9. Galactic model parameters of sub-classes of cataclysmic variables were also investigated.
