About this world
HD 149026 b is a Neptune-like planet orbiting HD 149026, a yellow, Sun-like star (type G0) 247 light-years from Earth. It is about 0.74 times the size of Jupiter and holds 0.38 Jupiter masses. It completes an orbit every 2.88 days at 0.044 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 1,626 K (1,353 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium. Its atmosphere has already been studied: 11 spectroscopic observations, 2 of them with the James Webb Space Telescope.
It was discovered in 2005 by radial velocity with Subaru Telescope. The star wobbles toward and away from us, Doppler-shifting its spectrum.