About this world
HD 22946 d is a sub-Neptune orbiting HD 22946, a yellow-white F-type star (type F7/F8V) 205 light-years from Earth. It is about 2.6 times the size of Earth and holds 27 Earth masses. It completes an orbit every 47.4 days at 0.3 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 546 K (273 °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. HD 22946 has 3 known planets; the others are TOI-411 b and TOI-411 c.