About this world
TOI-1859 b is a Neptune-like planet orbiting TOI-1859, a yellow-white F-type star 732 light-years from Earth. It is about 0.87 times the size of Jupiter. It completes an orbit every 63.5 days at 0.34 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.57).
Its equilibrium temperature is about 615 K (342 °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.