About this world
HD 156668 c is a Neptune-like planet orbiting HD 156668, an orange dwarf (type K2) 79.4 light-years from Earth. It is about 0.55 times the size of Jupiter (its size estimated from its mass), with at least 0.099 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 2.22 years at 1.6 AU from its star.
Its equilibrium temperature is about 166 K (−107 °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 2021 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 156668 has 2 known planets; the others are HD 156668 b.