HAT-P-27b: A HOT JUPITER TRANSITING A G STAR ON A 3 DAY ORBIT

We report the discovery of HAT-P-27b, an exoplanet transiting the moderately bright G8 dwarf star GSC 0333-00351 ( V = 12.214). The orbital period is 3.039586 ± 0.000012 days, the reference epoch of transit is 2455186.01879 ± 0.00054 (BJD), and the transit duration is 0.0705 ± 0.0019 days. The host star with its effective temperature 5300 ± 90 K is somewhat cooler than the Sun and is more metal-rich with a metallicity of +0.29 ± 0.10. Its mass is 0.94 ± 0.04 M ☉ and radius is 0.90 +0.05 − 0.04 R ☉ . For the planetary companion we determine a mass of 0.660 ± 0.033 M J and radius of 1.038 +0.077 − 0.058 R J . For the 30 known transiting exoplanets between 0.3 M J and 0.8 M J , a negative correlation between host star metallicity and planetary radius and an additional dependence of planetary radius on equilibrium temperature are confirmed at a high level of statistical significance.