About this world
GJ 887 d is a sub-Neptune orbiting GJ 887, a cool red dwarf (type M1V) 10.7 light-years from Earth. It is about 2.3 times the size of Earth (its size estimated from its mass), with at least 6.1 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 50.8 days at 0.21 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 241 K (−32 °C), which places it in the conservative habitable zone: the band where liquid water could exist on a rocky surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2026 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. GJ 887 has 4 known planets; the others are GJ 887 e, GJ 887 b and GJ 887 c.