About this world
TOI-125 c is a sub-Neptune orbiting TOI-125, an orange dwarf (type K0V) 362 light-years from Earth. It is about 2.8 times the size of Earth and holds 6.6 Earth masses. It completes an orbit every 9.15 days at 0.081 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 828 K (555 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium. Its atmosphere has already been studied: 2 spectroscopic observations, all of them with the James Webb Space Telescope.
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. TOI-125 has 3 known planets; the others are TOI-125 b and TOI-125 d.