2006ApJ...650.1160B

We report on the BVRI multiband follow-up photometry of the transiting extrasolar planet HD 189733b. We revise the transit parameters and find a planetary radius of R_P=1.154±0.033R_Jand an inclination of i_P=85°.79±0°.24. The new density (∼1 g/cm3) is significantly higher than the former estimate (∼0.75 g/cm3); this shows that from the current sample of nine transiting planets, only HD 209458 (and possibly OGLE-10b) have anomalously large radii and low densities. We note that due to the proximity of its parent star, HD 189733b currently has one of the most precise radius determinations among extrasolar planets. We calculate new ephemerides, P=2.218573±0.000020 days and T₀=2453629.39420±0.00024 (HJD), and estimate the timing offsets of the 11 distinct transits with respect to the predictions of a constant orbital period, which can be used to reveal the presence of additional planets in the system.