Which planet was named after the Roman God of water?

The blue planet was discovered in 1846 by Urbain Le Verrier, John Couch Adams, and Johann Galle by the use of mathematical predictions. It is named after the god of freshwater and sea because of its bluish appearance.

Neptune is the eighth and farthest-known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune orbits the Sun once every 164.8 years. It is named after the Roman god of the sea and has the astronomical symbol♆. Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation.The atmosphere of Neptune is made out of hydrogen, helium, and methane. The planet is basically a thick fog of water, ammonia, and methane over an Earth-sized solid center.High pressure experiments suggest large amounts of diamonds are formed from methane on the ice giant planets Uranus and Neptune, while some planets in other solar systems may be almost pure diamond.

In Roman mythology, Neptune is the god of freshwater and the sea. He is the counterpart of the Greek god Poseidon. In the Greek-influenced tradition, Neptune is the brother of Jupiter and Pluto. Salacia is his wife. Neptune is often pictured as having a three-pronged fisherman's spear. He is often shown to be an older man with a long beard.