About this world
BD+20 2457 b is a gas giant orbiting BD+20 2457, a giant star (type K2II) 5.02 thousand light-years from Earth. It is about 1.1 times the size of Jupiter (its size estimated from its mass), with at least 21 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 380 days at 1.4 AU from its star.
Its equilibrium temperature is about 1,160 K (887 °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 2009 by radial velocity with McDonald Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. BD+20 2457 has 2 known planets; the others are BD+20 2457 c.