The Transit Light Curve (TLC) Project. II. Two Transits of the Exoplanet   OGLE-TR-111b
  As part of our ongoing effort to measure exoplanet sizes and transit times with greater accuracy, we present I band observations of two transits of OGLE-TR-111b. The photometry has an accuracy of 0.15-0.20% and a cadence of 1-2 minutes. We derive a planetary radius of 1.067 +/- 0.054 Jupiter radii and a stellar radius of 0.831 +/- 0.031 solar radii. The uncertainties are dominated by errors in the photometry, rather than by systematic errors arising from uncertainties in the limb darkening function or the stellar mass. Both the stellar radius and the planetary radius are in agreement with theoretical expectations. The transit times are accurate to within 30 seconds, and allow us to refine the estimate of the mean orbital period: 4.0144479 +/- 0.0000041 days. 
Joshua N. Winn (MIT), Matthew J. Holman (CfA), Cesar I. Fuentes (CfA)