About this world
HIP 54373 b is a sub-Neptune orbiting HIP 54373, an orange dwarf (type K5V) 61 light-years from Earth. It is about 2.9 times the size of Earth (its size estimated from its mass), with at least 8.6 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 7.76 days at 0.063 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 581 K (308 °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. HIP 54373 has 2 known planets; the others are HIP 54373 c.