About this world
HD 17156 b is a gas giant orbiting HD 17156, a yellow, Sun-like star (type G5) 255 light-years from Earth. It is about 1.1 times the size of Jupiter and holds 3.3 Jupiter masses. It completes an orbit every 21.2 days at 0.16 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.68).
Its equilibrium temperature is about 888 K (615 °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 2007 by radial velocity with Subaru Telescope. The star wobbles toward and away from us, Doppler-shifting its spectrum.