About this world
HD 23472 b is a sub-Neptune orbiting HD 23472, an orange dwarf (type K4V) 127 light-years from Earth. It is about 2 times the size of Earth and holds 8.3 Earth masses. It completes an orbit every 17.7 days at 0.12 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 543 K (270 °C): far too hot for liquid water on its surface. By the "cosmic shoreline", it has likely held on to an atmosphere.
It was discovered in 2019 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction. HD 23472 has 5 known planets; the others are HD 23472 d, HD 23472 e, HD 23472 f and HD 23472 c.