About this world
GJ 3988 b is a super-Earth orbiting GJ 3988, a cool red dwarf (type M4.5V) 32.3 light-years from Earth. It is about 1.7 times the size of Earth (its size estimated from its mass), with at least 3.7 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 6.94 days at 0.041 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 348 K (75 °C): too cold for liquid water on its surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2023 by radial velocity with Calar Alto Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.