Abstract

Transiting planets are important for physical characterization of exoplanets. The light curves provide information such as the size of the planet and the inclination of the orbit. With radial velocity follow-ups and inclination measured from the transit light curve, the true mass of the planet is measurable. So far more than 2600 transiting exoplanets are known but all are relatively old (several 100 Myr to Gyrs). To close the gap at young ages, the YETI network (Young Exoplanet Transit Initiative) was established. It consists of ground based telescopes with mirror sizes of 0.4 to 2m, located at different longitudes all over the world. As a result, observations are continuous which eliminates gaps in the light curves and decreases the number of missed transits. The targets of the YETI network are young open clusters, which provide a large number of young stars with similar properties. The first target, which is part of my research, was Trumpler 37 with an age of 4 Myr. During a time span of three years, 60,000 images from 12 telescopes have been obtained for this cluster. Two transiting candidates were found along with 400 other variable stars. Follow-up observation was done for these transiting candidates and young eclipsing binaries and other young stars to analyse the systems. Through these observations, it was determined that the transit candidate signals were false positives. We are also monitoring 25 Ori (7 Myr), IC 348 (2 Myr), Col 69 (5 Myr) and NGC 1980 (5 Myr) in the YETI consortium. One transiting planet was found around a member star of 25 Ori. The analysis is still in progress. The follow-up is still ongoing but in between a direct imaging planet was found around the same host star.