About this world
HAT-P-11 b is a Neptune-like planet orbiting HAT-P-11, an orange dwarf (type K4) 123 light-years from Earth. It is about 4.4 times the size of Earth and holds 25 Earth masses. It completes an orbit every 4.89 days at 0.053 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.25).
Its equilibrium temperature is about 838 K (565 °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: 13 spectroscopic observations, 4 of them with the James Webb Space Telescope.
It was discovered in 2010 by transit with HATNet. A planet crosses its star and dims it by a tiny, periodic fraction. HAT-P-11 has 2 known planets; the others are HAT-P-11 c.