About this world
55 Cnc d is a gas giant orbiting 55 Cnc, a yellow, Sun-like star (type G8V) 41 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass) and holds 3.9 Jupiter masses. It completes an orbit every 13.1 years at 5.6 AU from its star.
Its equilibrium temperature is about 105 K (−168 °C): too cold for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2002 by radial velocity with Lick Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. 55 Cnc has 5 known planets; the others are 55 Cnc e, 55 Cnc b, 55 Cnc c and 55 Cnc f.