About this world
HIP 107772 b is a sub-Neptune orbiting HIP 107772, a cool red dwarf (type M0V) 77.1 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 55.2 days at 0.24 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 281 K (8 °C), which places it in the optimistic habitable zone: the band where liquid water could exist on a rocky surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2020 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum.