K2-254 is a star with 0.71 times the mass of the Sun, and 0.67 times its radius. It is located 742.90 light years away from the solar system.
K2-254 is known to have 2 exoplanets in orbit around it.
K2-254 b was discovered by the K2 observatory, in 2018-08, using the transit method. Its semi-major axis is 0.04 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of K2-254 b is 3.307 times the mass of Earth. The radius of K2-254 b is 1.630 that of Earth. At 3.307 Earth masses, K2-254 b is a so called Super Earth. Super Earths could be terrestrial worlds like Earth, but they could also be ocean worlds or terrestrial worlds wrapped in a substantial atmosphere, in which case some refer to them as Mini Neptunes. No Super Earths are known to exist in our solar system, but if it exists, the so-called Planet Nine could very well be a super Earth, as it is hypothesized to have a mass between five and ten Earth masses.
K2-254 c was discovered by the K2 observatory, in 2018-08, using the transit method. Its semi-major axis is 0.09 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of K2-254 c is 5.438 times the mass of Earth. The radius of K2-254 c is 2.190 that of Earth. At more than 10 Earth masses, K2-254 c 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.