About this world
BD-210397 b is a gas giant orbiting BD-210397, an orange dwarf (type K7V) 77.4 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 0.67 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 5.18 years at 2.6 AU from its star.
Its equilibrium temperature is about 104 K (−169 °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 radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. BD-210397 has 2 known planets; the others are BD-210397 c.