HAT-P-15 is a Sun-like G-type star (about 1.00 solar masses, 5,568 K, 1.07 solar radii), 193 light-years from Earth. HAT-P-15 b is a 1.94-Jupiter-mass companion, with an orbital period of 10.9 days, on an eccentric orbit (e ≈ 0.19), discovered in 2010 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. The planet's marked eccentricity suggests past scattering events or perturbations from unseen companions. The planet's large radius (11.9 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.