Pluto’s Newly Discovered Moons Get Official Names

The artist’s concept above shows the Pluto system from the surface of one of its tiny moons.Credit: NASA, ESA and G. Bacon (STScI)

Back in February we told you about an online naming contest for Pluto’s two newly discovered, smallest moons (P4 and P5). Now, nearly half million votes later, the moons have their official names.

Formally approved by the International Astronomical Union (IAU), the governing body that officially names celestial objects,  P4,  which is 15 miles (20 kilometers) across, has been named Kerberos, after the three-headed dog of ancient Greek legend. P5, at 20 miles (30 kilometers) in diameter, will now be known as Styx, after the mythological river that leads to the realm of the dead.

The new cosmic recruits join the family Pluto’s three other moons–Charon, Nix and Hydra–all named for characters associated with the Underworld of Greek and Roman mythology.

Dwarf planet Pluto has five moons, two of which have now received their official names. Courtesy of NASA, ESA, and M. Showalter (SETI Institute)
Dwarf planet Pluto has five moons, two of which have now received their official names. Courtesy of NASA, ESA, and M. Showalter (SETI Institute)

Both Kerberos and Styx were fist spotted by the Hubble Space Telescope in 2011 and 2012, as part of a survey of the Pluto system in preparation for a NASA probe flying by the dwarf planet in 2015. The spacecraft, called New Horizon, is still 600 million miles (1 billion kilometers) from the icy planet. But when it arrives in the neighborhood New Horizon is expected to get up-close portraits of Pluto’s recently discovered moons.

Vulcan Controversy?

This cosmic contest, which was started as a public educational initiative by the scientists who found these tiny moons, turned out to be quite popular worldwide. By the time the poll closed there were over 450,000 votes with front runners that included, other than the eventual winners, Persephone,Orpheus and the top vote getter – Vulcan.

However to the dismay of legions of Star Trek fans–and to the moons’ discoverer–the name ‘Vulcan’ did not make the grade with professional astronomers . It had been proposed by actor William Shatner, a.k.a Captain James T. Kirk.

“The IAU gave serious consideration to this name, which happens to be shared by the Roman god of volcanoes,”read an official statement from the SETI Institute, which had sponsored the naming contest. “However, because that name has already been used in astronomy, and because the Roman god is not closely associated with Pluto, this proposal was rejected.”

Within minutes of the announcement Shatner tweeted his disappointment.

What would Mr. Spock have to say about this decision?

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Changing Planet

Meet the Author
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.