The Transit Light Curve Project. VIII. Six Occultations of the Exoplanet TrES-3

We present photometry of the exoplanet host star TrES-3 spanning six occultations (secondary eclipses) of its giant planet. No flux decrements were detected, leading to 99%-confidence upper limits on the planet-to-star flux ratio of 2.4 × 10^-4, 5.0 × 10^-4, and 8.6 × 10^-4 in the i-, z-, and R-bands respectively. The corresponding upper limits on the planet's geometric albedo are 0.30, 0.62, and 1.07. The upper limit in the i-band rules out the presence of highly reflective clouds, and is only a factor of 2-3 above the predicted level of thermal radiation from the planet.