About this world
Kepler-37 e is an Earth-sized planet orbiting Kepler-37, a yellow, Sun-like star 208 light-years from Earth. It is about 0.37 times the size of Earth, with at least 8.1 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 51.2 days at 0.25 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 401 K (128 °C): far too hot for liquid water on its surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2014 by transit with Kepler. A planet crosses its star and dims it by a tiny, periodic fraction. Kepler-37 has 4 known planets; the others are Kepler-37 b, Kepler-37 c and Kepler-37 d.