About this world
TOI-5678 b is a Neptune-like planet orbiting TOI-5678, a yellow, Sun-like star (type G7V) 539 light-years from Earth. It is about 4.9 times the size of Earth and holds 20 Earth masses. It completes an orbit every 47.7 days at 0.25 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 513 K (240 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2023 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.