About this world
GJ 433 d is a sub-Neptune orbiting GJ 433, a cool red dwarf (type M2V) 29.6 light-years from Earth. It is about 2.1 times the size of Earth (its size estimated from its mass), with at least 5.2 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 36.1 days at 0.18 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 280 K (7 °C), which places it in the conservative habitable zone: the band where liquid water could exist on a rocky surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2020 by radial velocity with Multiple Facilities. The star wobbles toward and away from us, Doppler-shifting its spectrum. GJ 433 has 3 known planets; the others are GJ 433 b and GJ 433 c.