About this world
HIP 35173 b is a sub-Neptune orbiting HIP 35173, an orange dwarf (type K2V) 108 light-years from Earth. It is about 3.6 times the size of Earth (its size estimated from its mass), with at least 13 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 41.5 days at 0.22 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 444 K (171 °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 2019 by radial velocity with Las Campanas Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.