About this world
K2-198 b is a Neptune-like planet orbiting K2-198, a yellow, Sun-like star 361 light-years from Earth. It is about 4.2 times the size of Earth. It completes an orbit every 17 days at 0.12 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 716 K (443 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2018 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. K2-198 has 3 known planets; the others are K2-198 c and K2-198 d.