About this world
alf Ari b is a gas giant orbiting alf Ari, a giant star (type K2III) 65.9 light-years from Earth. It is about 1.2 times the size of Jupiter (its size estimated from its mass), with at least 1.8 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 381 days at 1.2 AU from its star, on a strongly elongated orbit (e = 0.25).
Its equilibrium temperature is about 747 K (474 °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 2010 by radial velocity with Bohyunsan Optical Astronomical Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum.