Abstract:
We report a transit timing study of the transiting exoplanetary system HD 189733. In total,
we observed 10 transits in 2006 and 2008 with the 2.6-m Nordic Optical Telescope, and two
transits in 2007 with the 4.2-m William Herschel Telescope. We used Markov Chain Monte
Carlo simulations to derive the system parameters and their uncertainties, and our results
are in a good agreement with previously published values. We performed two independent
analyses of transit timing residuals to place upper mass limits on putative perturbing planets.
The results show no evidence for the presence of planets down to 1 Earth mass near the 1:2
and 2:1 resonance orbits, and planets down to 2.2 Earth masses near the 3:5 and 5:3 resonance
orbits with HD 189733b. These are the strongest limits to date on the presence of other planets
in this system.
