2011AJ....141..179C

We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706±0.056R_Jup and 1.736±0.092R_Jup, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827±0.055R_Jup, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from strict periodicity. For TrES-4, our relatively recent observations allow for improvement in the orbital ephemerides, which is useful for planning future observations.