Pluto's moons named

Friday, June 23, 2006 

Artist conception of Hydra (foreground), Pluto & Charon (background), and Nix (bright dot center left)

The two recently discovered moons of the planet Pluto were officially named Hydra and Nix by the International Astronomical Union, the internationally recognized authority for assigning designations to celestial bodies.

The moons were discovered in May last year by the Pluto Companion Search Team, a team of scientists from the Southwest Research Institute (SwRI), the Johns Hopkins University's Applied Physics Laboratory (APL), the Space Telescope Science Institute and Lowell Observatory, using images taken from the Hubble space telescope. The moons were designated as S/2005 P1 (Hydra) and P2 (Nix) upon discovery.

Their discovery comes 27 years after the discovery of Pluto's largest moon Charon. The two moons are roughly 5000 times fainter than Pluto and two to three times farther from Pluto, compared to Charon. The two bodies are roughly 50 km in diameter.

The names are derived from Greek mythology, where Hydra is a monster with the body of a serpent and nine heads and Nix is the goddess of darkness and night. Nix is also the mother of Charon, an allusion to the giant impact which is believed to have created the three satellites of Pluto, with Charon borne of the material from which Nix formed. Pluto himself is the god of the underworld.

Sources

• "Pluto's two small moons christened Nyx and Hydra" — Southwest Research Institute, June 22, 2006
• Alicia Chang. "Pluto's Newly Found Moons Named Nyx, Hydra" — Associated Press, June 22, 2006