Breus V. Orbital and spin variability of magnetic cataclysmic binary stars

Thesis for a Candidate's degree on Physics and Mathematics. Speciality 01.03.02 -astrophysics, radioastronomy. - Odessa National Maritime University, Ministry of Education and Science of Ukraine, Odessa, 2013. Thesis is devoted to the study of the structure and evolution of magnetic cataclysmic binary stars. For the first time the values of the orbital periods and periods of the spin rotation of the white dwarf in the intermediate polar V1323 Her, EX Hya, V405 Aur, MU Cam, FO Aqr, PQ Gem, 1RXS J2133.7 +5107 were determined with high accuracy. In particular, the accuracy of the period of V1323 Her is 250 times better then that determined by discoverers. The spin and orbital period variations were studied for the selected binary systems. Suspected the presence of low-mass red dwarf orbiting a close binary system V405 Aur, so this system may belong to a rare class of cataclysmic systems with a third body. The hypothesis by Mauche et al. of the cubic behaviour of the O-C for the spin period of the white dwarf in the system EX Hya is disproved. The hypothesis by Piirola et al. of increase of the spin period in the V405 Aur is disproved, as recent data show a strong period decrease. The change of amplitude of circular polarization variability in the asynchronous polar BY Cam was detected. We got the dependence of the limit values of orbit inclination, and the inclination of the orbit corresponding to the observed value of the minimum duration on the mass of the white dwarf for the eclipsing polar OTJ071126+440405. For the first time, we obtained estimates of the physical parameters of the eclipsing polar OTJ071126+440405: the mass of the white dwarf, the distance between the components, the radius of the white dwarf, the orbital velocity, size of the area of radiation. Estimates of the angles between the line of centres and the magnetic axis, the basis of the accretion column and the line of centres were obtained. We developed PolarObs software package for processing of photopolarimetric observations obtained using a photometer-polarimeter with rapidly rotating analyzer constructed by Yu. S. Efimov and N.M.Shakhovskoy at the largest in Ukraine 2.6m G. A. Shain Telescope (Crimean Astrophysical Observatory). For processing photometric observations and time series we developed a computer program Variable Stars Calculator. We corrected the value of the orbital period of eclipsing binary V442 Cam, which is in the field of view of one of studied objects. The value of the orbital period determined is by 4500 times more accurate than previously published data. A new variable star VSX J180243.9 +400331 was discovered. It was classified as an Algol-type eclipsing binary. The orbital period and other characteristics of variability were determined. The results included into the databases of the international program "Inter-Longitude Astronomy" and the project "Ukrainian Virtual Observatory".