HD 221416 and Its Jupiter-Like Planet

HD 221416 is a K-type star 312 light-years away. Its spectral type, K0 IV/V, places it in the cooler K class, and it has one known planet. The star is 4.9 billion years old, with a mass of 1.21 solar masses and a radius of 2.94 solar radii. Its temperature is 5080 K.

The planet HD 221416 b was discovered in 2019 by the transit method, in which a planet passing in front of its star from our viewpoint causes a small dip in observed brightness; repeated dips help establish orbital periods. It orbits HD 221416 every 14.3 days. Its radius is 9.17 Earth radii, and its mass is 60.5 Earth masses. With a radius more than four times Earth's, it qualifies as Jupiter-like, a size class based on radius rather than composition. Its mean density is 0.432 g/cm³, 0.0785 times Earth's. The star's mass and radius are larger than the Sun's, while its temperature is cooler.