The Kepler-221 Exoplanetary System
Kepler-221 is a star with 0.7150000000000001 times the mass of the Sun, and 0.82 times its radius. It is located 1270.54 light years away from the solar system.
Kepler-221 is known to have 4 exoplanets in orbit around it.
Kepler-221 b was discovered by the Kepler observatory using the transit method. Its discovery was announced in 2014-03. Its semi-major axis is 0.04 astronomical units, as compared to Earth's which is 1 astronomical unit. It takes 2.80 Earth days to complete an orbit around its host star, Kepler-221.
The mass of Kepler-221 b is 3.51 times the mass of Earth. The radius of Kepler-221 b is 1.71 that of Earth. At 3.51 Earth masses, Kepler-221 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.