Follow-up photometry of HAT-P-27

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+/-90K is somewhat cooler than the Sun and is more metal-rich with a metallicity of +0.29+/-0.10.

Its mass is 0.94+/-0.04M_{sun}_ and radius is 0.90^+0.05^_-0.04_R_{sun}_. For the planetary companion we determine a mass of 0.660+/-0.033M_J_ and radius of 1.038^+0.077^_-0.058_R_J_. For the 30 known transiting exoplanets between 0.3M_J_ and 0.8M_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.