HATS-59 and Its Two Known Planets

HATS-59 is a star 2100 light-years away with two known planets. The host is 4.3 billion years old and has a mass of 1.04 solar masses and a radius of 1.04 solar radii. Its temperature of 5670 K is cooler than the Sun's. The planets were both discovered in 2018.

HATS-59 b is Jupiter-like and was found by the transit method, which detects the dip in starlight when a planet crosses in front of its star. It has a mass of 256 Earth masses and a radius of 12.6 Earth radii, both larger than Earth's corresponding values, and a mean density of 0.702 g/cm³, 0.127 times Earth's. Its orbital period is 5.42 days, the shortest among the listed planets.

HATS-59 c was found by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Its minimum mass is 4040 Earth masses, roughly 12.7 times Jupiter's mass. Its orbital period is 1420 days, the longest among the listed planets.