An astronomer studying archived images of Neptune taken by the Hubble Space Telescope has found a 14th moon orbiting the planet, NASA said on Monday (July 15).

Estimated to be about 12 miles (20 km) in diameter, the moon is located about 65,400 miles (105,251 km) from Neptune.

Astronomer Mark Showalter, with the SETI Institute in Mountain View, California, was searching Hubble images for moons inside faint ring fragments circling Neptune when he decided to run his analysis program on a broader part of the sky.

Follow-up analysis of other archived Hubble images of Neptune verified the object was a moon.

Neptune's largest moon, Triton, was discovered in 1846, just days after the planet itself was found. Nereid, Neptune's third largest moon was found in 1949.

Presented by Adam Justice