HAT-P-16b: A 4 MJ PLANET TRANSITING A BRIGHT STAR ON AN ECCENTRIC ORBIT

We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting the V = 10.8mag F8 dwarf GSC 279201700, with a period P = 2.775960 +/- 0.000003 days, transit epoch T-c = 2455027.59293 +/- 0.00031 (BJD10), and transit duration 0.1276 +/- 0.0013 days. The host star has a mass of 1.22 +/- 0.04 (M)circle dot, radius of 1.24 +/- 0.05 R-circle dot, effective temperature 6158 +/- 80 K, and metallicity [Fe/H] = + 0.17 +/- 0.08. The planetary companion has a mass of 4.193 +/- 0.094 M-J and radius of 1.289 +/- 0.066 R-J, yielding a mean density of 2.42 +/- 0.35 g cm(-3). Comparing these observed characteristics with recent theoretical models, we find that HAT-P-16b is consistent with a 1 Gyr H/He-dominated gas giant planet. HAT-P-16b resides in a sparsely populated region of the mass-radius diagram and has a non-zero eccentricity of e = 0.036 with a significance of 10s.