About this world
HD 105618 b is a Neptune-like planet orbiting HD 105618, a yellow, Sun-like star 229 light-years from Earth. It is about 5.4 times the size of Earth (its size estimated from its mass), with at least 25 Earth masses (a minimum, measured by radial velocity). It completes an orbit every 10 days at 0.091 AU from its star, closer than Mercury is to the Sun, on a strongly elongated orbit (e = 0.46).
Its equilibrium temperature is about 1,023 K (750 °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. HD 105618 has 2 known planets; the others are HD 105618 c.