About this world
WASP-18 b is a gas giant orbiting WASP-18, a yellow-white F-type star (type F6IV-V) 403 light-years from Earth. It is about 1.2 times the size of Jupiter and holds 10 Jupiter masses. It completes an orbit every 22.6 hours at 0.02 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 2,429 K (2,156 °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: 34 spectroscopic observations, 3 of them with the James Webb Space Telescope.
It was discovered in 2009 by transit with SuperWASP. A planet crosses its star and dims it by a tiny, periodic fraction.