About this world
HIP 97166 c is a sub-Neptune orbiting HIP 97166, an orange dwarf (type K0V) 215 light-years from Earth. It is about 2.8 times the size of Earth (its size estimated from its mass), with at least 8 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 16.4 days at 0.12 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 642 K (369 °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 2021 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. HIP 97166 has 2 known planets; the others are HIP 97166 b.