About this world
55 Cnc c is a Neptune-like planet orbiting 55 Cnc, a yellow, Sun-like star (type G8V) 41 light-years from Earth. It is about 0.76 times the size of Jupiter (its size estimated from its mass) and holds 0.17 Jupiter masses. It completes an orbit every 44.4 days at 0.25 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 499 K (226 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2004 by radial velocity with McDonald 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 f and 55 Cnc d.