About this world
HD 77946 b is a sub-Neptune orbiting HD 77946, a yellow-white F-type star (type F5) 324 light-years from Earth. It is about 2.9 times the size of Earth and holds 11 Earth masses. It completes an orbit every 6.53 days at 0.073 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.21).
Its equilibrium temperature is about 1,129 K (856 °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 2024 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction.