HAT-P-2 and Its Two Known Planets

HAT-P-2 is an F8 star located 417 light-years away. The star is 2.6 billion years old and has a mass of 1.3 solar masses, a radius of 1.47 solar radii, and a temperature of 6290 K. Its reported mass and radius are larger than the Sun's, and it is hotter than the Sun. Two planets are known to orbit this host.

HAT-P-2 b was discovered in 2007 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it. The planet has a minimum mass of 2740 Earth masses, roughly 8.62 times Jupiter's mass, and an orbital period of 5.63 days - the shortest year among the listed planets.

HAT-P-2 c was discovered in 2023 by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion; repeated wobbles reveal the planet and its orbital period. It has a mass of 3400 Earth masses, roughly 10.7 times Jupiter's mass, and an orbital period of 8500 days - the longest year among the listed planets.