Investigation of transit timing variation to XO-2b ve QATAR-3b exoplanets

In this thesis work, transition observations of exoplanets XO-2b and Qatar-3b were carried out with the 50 cm Ritchey-Chretien type telescope (UT50) at UZAYMER Observatory in the university of Çukurova. In addition to the UT50 observations, data taken with T35, T100 and TESS were used. Planets which are known with their transitions, located in XO-2 and Qatar-3 systems which have exoplanets, are expected to have consecutive transitions. The consecutiveness of the transition times of these two systems were monitored using the mid-transition times and possible perturbation effects were investigated, nevertheless no conclusion could be attained. As a result of the best model linear fits of both TTV dataset; The linear ephemeris were determined for XO-2b and Qatar-3b as T(BJD-TDB)=2457760.2527(33)+2.61585927xE and 245768.799410(11)+2.50790292(25)xE, respectively. The parameter values calculated as a result of the analysis of the transition light curves of XO-2b are compatible with the results given by Burke et al (2007) and Fernandez et al (2009). On the other hand, the analysis results of Qatar-3b are compatible with results given by Alsubai et al (2017). The Lomb-Scargle (LS) periodogram was used in the frequency analysis of the mid-transition times, and no significant period change was found for XO-2b and Qatar-3b. Keywords: Planetary Systems, Planet-Star Interactions, Exoplanet, TV, Lomb Scargle Periodogram, Orbital Period, Ephemeris