About this world
HD 203387 b is a gas giant orbiting HD 203387, an orange dwarf 201 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 3.5 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 513 days at 1.8 AU from its star, on a strongly elongated orbit (e = 0.73).
Its equilibrium temperature is about 610 K (337 °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 2022 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum. HD 203387 has 2 known planets; the others are HD 203387 c.