About this world
HD 106315 c is a Neptune-like planet orbiting HD 106315, a yellow-white F-type star (type F5V) 357 light-years from Earth. It is about 4.3 times the size of Earth and holds 15 Earth masses. It completes an orbit every 21.1 days at 0.15 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.22).
Its equilibrium temperature is about 886 K (613 °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: 4 spectroscopic observations, 1 of them with the James Webb Space Telescope.
It was discovered in 2017 by transit with K2. A planet crosses its star and dims it by a tiny, periodic fraction. HD 106315 has 2 known planets; the others are HD 106315 b.