About this world
GJ 9827 b is a super-Earth orbiting GJ 9827, an orange dwarf (type K7V) 96.7 light-years from Earth. It is about 1.4 times the size of Earth and holds 4.3 Earth masses. It completes an orbit every 1.21 days at 0.019 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 1,035 K (762 °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. Its atmosphere has already been studied in one spectroscopic observation by the James Webb Space Telescope.
It was discovered in 2017 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. GJ 9827 has 3 known planets; the others are GJ 9827 c and GJ 9827 d.