Spectroscopic photometric applications in some algol type binaries

In this study, the spectroscopic and/or photometric data of Algol type eclipsing binaries, IO UMa, AT Peg and RY Gem have been analyzed. The radial velocities of the components of IO UMa and AT Peg were determined using the spectra of these systems taken from Catania Astrophysics Observatory. The orbit solutions of IO UMa and AT Peg were made and the mass ratio values are determined as 0,136±0,002 and 0,488±0,007, respecitvely. The projected rototional velocities (v sini) of the hotter components of IO UMa and AT Peg were measured and found that these components rotate almost synchronizedly.The photometric observations of IO UMa and AT Peg were made at Çanakkale Onsekiz Mart University Observatory and the BVR light curves of these systems were obtained. In this work, the analysis of photometric and spectroscopic data of IO UMa was made for the first time. The BVR light curves of IO UMa and AT Peg were analyzed and the photometric parameters were determined. The third light contribution to the total light of AT Peg (with a rate of 25%) was found. In addition to this, the short period variations in the light curve of IO UMa caused by the hotter component were determined. It was found that the massive component of IO UMa is a ? Scuti variable with four frequencies. The ASAS-V light curve of the long period Algol RY Gem was analyzed and the photometric rotational parameter of the hotter component of the system was tested during the analysis. By studying the orbital period variation of AT Peg, it was found that the period is decreasing with a rate of 0,03 s/year. And also, the periodic variation in the O-C diagram of the system may be caused by a third body around the eclipsing pair. The minimum mass of the hypotetical component was found to be 0,5 M ? .Finally, combining the orbital and light curve solutions, the absolute parameters of the components of IO UMa, AT Peg and RY Gem and the distance of these systems were determined.