Transit Timing Variations analysis in exoplanet host stars

In June of 2011 we started a continuous photometric monitoring of transiting planets host stars in the southern hemisphere, with the aim of searching for periodic variations in their mid-transit times. Such variations (or TTVs) are produced by the gravitational action of other bodies in the system that disturb the semimajor axis and therefore the orbital period of the transiting planet. The smaller the mass of the disturber the lower the amplitude of the variation and therefore high precision (tens of seconds) is required to measure the central transit times. In this paper, we present a full analysis of TTVs of some of the objects with transits observed from 2011 to the present.