About this world
K2-157 c is a Neptune-like planet orbiting K2-157, a yellow, Sun-like star (type G9V) 973 light-years from Earth. It is about 0.54 times the size of Jupiter (its size estimated from its mass), with at least 0.097 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 25.9 days at 0.17 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 587 K (314 °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 2025 by radial velocity with Paranal Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. K2-157 has 3 known planets; the others are K2-157 b and K2-157 d.