About this world
TOI-1823 b is a Neptune-like planet orbiting TOI-1823, an orange dwarf 234 light-years from Earth. It is about 0.67 times the size of Jupiter and holds 0.21 Jupiter masses. It completes an orbit every 38.8 days at 0.21 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 424 K (150 °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: 2 spectroscopic observations, all of them with the James Webb Space Telescope.
It was discovered in 2024 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.