K2-251 is a star with 0.52 times the mass of the Sun, and 0.49 times its radius. It is located 479.55 light years away from the solar system.
K2-251 is known to have 1 exoplanets in orbit around it.
K2-251 b was discovered by the K2 observatory, in 2018-08, using the transit method. Its semi-major axis is 0.07 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of K2-251 b is 6.137 times the mass of Earth. The radius of K2-251 b is 2.350 that of Earth. At more than 10 Earth masses, K2-251 b is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune in our solar system.