K2-128 is a star with 0.71 times the mass of the Sun, and 0.78 times its radius. It is located 373.90 light years away from the solar system.
K2-128 is known to have 1 exoplanets in orbit around it.
K2-128 b was discovered by the K2 observatory, in 2017-11, using the transit method. Its semi-major axis is 0.06 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of K2-128 b is 2.604 times the mass of Earth. The radius of K2-128 b is 1.420 that of Earth. At 2.604 Earth masses, K2-128 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.