Detection of period variations in extrasolar transiting planet   OGLE-TR-111b
  Two consecutive transits of planetary companion OGLE-TR-111b were observed in the I band. Combining these observations with data from the literature, we find that the timing of the transits cannot be explained by a constant period, and that the observed variations cannot be originated by the presence of a satellite. However, a perturbing planet with the mass of the Earth in an exterior orbit could explain the observations if the orbit of OGLE-TR-111b is eccentric. We also show that the eccentricity needed to explain the observations is not ruled out by the radial velocity data found in the literature. 
Rodrigo F. D\'iaz (1), Patricio Rojo (2), Mario Melita (1), Sergio   Hoyer (2), Dante Minniti (3,4), Pablo J.D. Mauas (1), M...