About this world
DMPP-9 b is a sub-Neptune orbiting DMPP-9, a yellow-white F-type star 357 light-years from Earth. It is about 3.9 times the size of Earth (its size estimated from its mass), with at least 14 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 12.7 days at 0.11 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.25).
Its equilibrium temperature is about 996 K (722 °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 radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum.