By tradition, the moons of Pluto have names associated with Hades and the underworld. But there's plenty of possibilities to choose from - and the discoverers of the planet's two tiniest moons are inviting the public to name them.
Pluto's three other moons are known as Charon, Nix and Hydra, but until now, the latest discoveries have been referred to as, simply, P4 and P5. They now need names derived from Greek or Roman mythology.
P4 was discovered in 2011 in images taken by the Hubble Space Telescope, while P5 was found a year later during a more intensive search. The moons are only 15 to 20 miles across.
"The Greeks were great storytellers and they have given us a colorful cast of characters to work with," says Mark Showalter, Senior Research Scientist at the Carl Sagan Center of the SETI Institute in Mountain View, California.
Visitors to the website will be able to submit suggestions which will be reviewed by the moons' discoverers and and, if they're good enough, be added to a ballot. There are already 12 names suggested: Acheron, Alecto, Cerberus, Erebus, Eurydice, Hercules, Hypnos, Lethe, Obol, Orpheus, Persephone and Styx.
"In 1930, a little girl named Venetia Burney suggested that Clyde Tombaugh name his newly discovered planet 'Pluto," says Showalter.
"Tombaugh liked the idea and the name stuck. I like to think that we are doing honor to Tombaugh's legacy by now opening up the naming of Pluto's two tiniest known moons to everyone."
The public can vote until February 25, 2013. The final names will be announced after their formal approval by Showalter and the teams of astronomers who made the discoveries, and will be approved by the International Astronomical Union.
Currently, Pluto is receiving extra attention from astronomers, as NASA's New Horizons spacecraft is slated to arrive there in July 2015.