HIP 34222 b: A Minimum-Mass Planet Orbiting a Cool Dwarf

HIP 34222 is a K5 star located 74.5 light-years from the Sun. Its reported mass is 0.63 solar masses, its radius is 0.619 solar radii, and its temperature is 4050 K. Each of these reported estimates is smaller or cooler than the corresponding solar value. One planet is known to orbit this star.

That planet, HIP 34222 b, was discovered in 2021 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion; repeated wobbles reveal the planet and its orbital period. Its minimum mass is 264 Earth masses, a lower bound on its true mass and larger than Earth's mass. HIP 34222 b completes one orbit in 160 days.