About this world
HD 81817 c is a gas giant orbiting HD 81817, a giant star (type K3III) 878 light-years from Earth. It is about 1.1 times the size of Jupiter (its size estimated from its mass), with at least 23 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 623 days at 2.3 AU from its star.
Its equilibrium temperature is about 1,199 K (925 °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 2022 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 81817 has 2 known planets; the others are HD 81817 b.