About this world
HD 144899 b is a Neptune-like planet orbiting HD 144899, a yellow-white F-type star 377 light-years from Earth. It is about 4.8 times the size of Earth (its size estimated from its mass), with at least 20 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 40.4 days at 0.24 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.82).
Its equilibrium temperature is about 771 K (498 °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 2022 by radial velocity with Multiple Observatories. The star wobbles toward and away from us, Doppler-shifting its spectrum.