Analysis of eclipsing twin binary systems

We need to understand stars, which are the cornerstones of the galaxies, to understand our galaxy and, therefore, the universe. Eclipsing binary systems have been playing the biggest role in advancement in modern astrophysics while providing detailed information about stars. If the mass ratio between components of a binary system is bigger than 0.95, that system is called a twin binary system, and if an eclipsing occurs in that system, called an eclipsing twin binary system. In this thesis, by analyzing Kepler Eclipsing Binary Catalog, we have selected 88 eclipsing twin binary candidate systems with circular orbits according to our criteria. After analysis, 43 of them were determined as twin binary systems. Photometric observations of these systems have been made, and colours of these systems obtained. After that, we have determined their spectral type from colour-colour diagrams. To test our spectral type results, we have calculated photometric distances of each system with the determined spectral type and compared the results with Gaia distances. As a result, spectral types of 34 eclipsing twin binary systems with circular orbits out of 43 have been obtained in harmony with Gaia distances. To determine eclipsing twin binary systems with an eccentric orbit, 47 systems have been selected from Kjurkchieva et al. (2017) as candidates. After analysis, 15 eccentric systems out of 47 have been determined as eclipsing twin binary systems with eccentric orbits. As a result, the spectral type distribution of 49 eclipsing twin binary systems has been analyzed with previous studies in the literature. Three systems, AN Cam, RS Ari, and V455 Aur, have been selected from SB9 for determining absolute parameters and metallicity. Initial orbital parameters of these three systems have been calculated, and detailed evolution calculations have been made via using calculated initial orbital parameters via using MESA evolution code. Also, we have selected well-studied 34 eclipsing twin binary systems from Eker et al. (2018) for determining initial orbital parameters via evolutionary analysis and discussed formation scenarios of twins.