Defocused Observations of Selected Exoplanet Transits with T100 at the TÜBİTAK National Observatory of Turkey (TUG)

Determining masses and radii of extrasolar planets with high precision is key to our understanding of their chemical composition, internal structure, and thereby their formation and evolution. Toward this goal we are applying the defocusing technique for the photometric observation of selected planetary systems with the 1 m Turkish telescope T100 at the TÜBİTAK National Observatory (TUG). In this contribution we present preliminary analyses of transit light curves obtained using this technique for the exoplanets KELT-3b, HAT-P-10b/WASP-11b, HAT-P-20b, and HAT-P-22b.