About this world
GJ 3929 b is an Earth-sized planet orbiting GJ 3929, a cool red dwarf (type M3.5V) 51.6 light-years from Earth. It is about 1.1 times the size of Earth and holds 1.8 Earth masses. It completes an orbit every 2.62 days at 0.025 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 568 K (295 °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: 5 spectroscopic observations, all of them with the James Webb Space Telescope.
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. GJ 3929 has 2 known planets; the others are GJ 3929 c.