About this world
HIP 99770 b is a gas giant orbiting HIP 99770, a white A-type star (type A5-A6) 131 light-years from Earth. It is about 1.1 times the size of Jupiter (its size estimated from its mass) and holds 17 Jupiter masses. It completes an orbit every 50.9 years at 16 AU from its star, on a strongly elongated orbit (e = 0.31).
Its equilibrium temperature is about 135 K (−138 °C): too cold for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2023 by direct imaging with Multiple Observatories. The planet itself is photographed, its star blocked by a coronagraph.