About this world
LHS 1903 d is a sub-Neptune orbiting LHS 1903, a cool red dwarf (type M) 116 light-years from Earth. It is about 2.5 times the size of Earth and holds 6 Earth masses. It completes an orbit every 12.6 days at 0.086 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 442 K (169 °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 2026 by transit with Transiting Exoplanet Survey Satellite (TESS). A planet crosses its star and dims it by a tiny, periodic fraction. LHS 1903 has 4 known planets; the others are LHS 1903 b, LHS 1903 c and LHS 1903 e.