About this world
K2-254 c is a sub-Neptune orbiting K2-254, an orange dwarf 743 light-years from Earth. It is about 2.2 times the size of Earth. It completes an orbit every 12.1 days at 0.092 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 551 K (278 °C): far too hot for liquid water on its surface. By the "cosmic shoreline", its star has probably stripped its atmosphere away, leaving bare rock.
It was discovered in 2018 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. K2-254 has 2 known planets; the others are K2-254 b.