About this world
TOI-1238 b is an Earth-sized planet orbiting TOI-1238, an orange dwarf (type K7/M0) 231 light-years from Earth. It is about 1.2 times the size of Earth and holds 3.8 Earth masses. It completes an orbit every 18.4 hours at 0.014 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.25).
Its equilibrium temperature is about 1,133 K (860 °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 2022 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction. TOI-1238 has 2 known planets; the others are TOI-1238 c.