HIP 56640 and Its Planet

HIP 56640 is a K-type giant star located 399 light-years from Earth. One planet orbits this host. The star's spectral type, K1 III, places it in the cooler K class. Its reported temperature of 4770 K is cooler than the Sun's, and its reported radius of 4.93 solar radii is larger than the Sun's. The star is 9.15 billion years old, with a mass of 1.04 solar masses. Its only known planet is HIP 56640 b.

HIP 56640 b was discovered in 2021 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. The planet's reported mass estimate of 2150 Earth masses is larger than Earth's and roughly 6.77 times Jupiter's mass. It completes one orbit every 2680 days.