Homogeneous studies of transiting extrasolar planets - IV. Thirty systems with space-based light curves

Abstract

I calculate the physical properties of 32 transiting extrasolar planet and brown dwarf systems from existing photometric observations and measured spectroscopic parameters. The systems studied include fifteen observed by CoRoT, ten by Kepler and five by the Deep Impact spacecraft. Inclusion of the objects studied in previous papers leads to a sample of 58 transiting systems with homogeneously measured properties. The Kepler data include observations from Quarter 2, and my analyses of several of the systems are the first to be based on short-cadence data from this satellite. The light curves are modelled using the JKTEBOP code, with attention paid to the treatment of limb darkening, contaminating light, eccentricity, correlated noise, and numerical integration over long exposure times. The physical properties are derived using constraints from five sets of theoretical stellar model predictions. An alternative approach using a calibration from eclipsing binary star systems is explored and found to give comparable numbers. My results are in good agreement with published properties for most of the transiting systems, but discrepancies are identified for CoRoT-5, CoRoT-8, CoRoT-13, Kepler-5 and Kepler-7. Many of the errorbars quoted in the literature are underestimated. Refined orbital ephemerides are given for CoRoT-8 and for the Kepler planets. Asteroseismic constraints on the density of the host stars are in good agreement with the photometric equivalents for HD 17156 and TrES-2, but not for HAT-P-7 and HAT-P-11. Complete error budgets are generated for each transiting system. Whilst most would benefit from further photometry and spectroscopy, HD 17156, HD 80606, HAT-P-7 and TrES-2 are now extremely well characterised. HAT-P-11 is an exceptional candidate for studying starspots. The orbital ephemerides of some transiting systems are becoming uncertain and they should be re-observed.