About this world
G 261-6 b is an Earth-sized planet orbiting G 261-6, a cool red dwarf (type M5.5V) 34.7 light-years from Earth. It is about 1.1 times the size of Earth (its size estimated from its mass), with at least 1.4 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 5.45 days at 0.03 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 322 K (49 °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 2025 by radial velocity with Calar Alto Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.