About this world
HATS-75 b is a Neptune-like planet orbiting HATS-75, a cool red dwarf 636 light-years from Earth. It is about 0.88 times the size of Jupiter and holds 0.49 Jupiter masses. It completes an orbit every 2.79 days at 0.033 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 772 K (499 °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: 4 spectroscopic observations, all of them with the James Webb Space Telescope.
It was discovered in 2021 by transit with HATSouth. A planet crosses its star and dims it by a tiny, periodic fraction.