About this world
GJ 238 b is an Earth-sized planet orbiting GJ 238, a cool red dwarf (type M2.5V) 49.6 light-years from Earth. It is about 0.57 times the size of Earth. It completes an orbit every 1.74 days at 0.021 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 758 K (485 °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 2024 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.