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Scientists go with people's choice for Pluto moons: Vulcan, Cerberus

An image from the Hubble Space Telescope shows Pluto and its largest moon, Charon, surrounded by four smaller moons. Astronomers have proposed naming P4 and P5 after Vulcan and Cerberus.
An image from the Hubble Space Telescope shows Pluto and its largest moon, Charon, surrounded by four smaller moons. Astronomers have proposed naming P4 and P5 after Vulcan and Cerberus.M. Showalter / NASA / ESA

Astronomers have decided to go with the people's choice and propose Vulcan and Cerberus (or Kerberos) as the names for Pluto's tiniest known moons, one of the discovery team's leaders said Tuesday. Vulcan bubbled up to the top of the list in a non-binding "Pluto Rocks" contest in February, thanks in part to a strong endorsement from "Star Trek" captain William Shatner. The International Astronomical Union, which traditionally approves celestial names, still has to weigh in on the discoverers' proposal.

"We did not feel rigidly bound by the vote totals, but in the end we decided that Vulcan and Cerberus/Kerberos were pretty good names," said Mark Showalter, a planetary scientist at the SETI Institute who organized the contest. Showalter discussed the selection process in an email to NBC News after Nature reported that the IAU was considering the names.

Shatner, who played Captain James T. Kirk on the original "Star Trek" series, proposed the name Vulcan in honor of the home planet of Kirk's pointy-eared science officer, Mr. Spock. He put out the word to more than a million Twitter followers, and Vulcan ended up receiving 174,062 of the 450,324 votes cast. Cerberus was No. 2 on the list, with 99,434 votes.

Astronomers needed two names — one for the Plutonian moon P4, discovered in 2011; and another for P5, found in 2012. Although Vulcan and Cerberus were the favorites, it was not assured that the discovery team would go with those choices.

Stating the case

Traditionally, Pluto's moons are named after figures of the underworld from Greek or Roman mythology. Cerberus fit that scheme, because that was the name of the dog that guarded the gates of the Greco-Roman underworld. Vulcan, which is the name of the Roman god of fire as well as Mr. Spock's home world, posed more of a challenge.

"For the IAU proposal, I had to make the connection between Vulcan and the Greco-Roman underworld, because I knew that the nomenclature working groups would not be swayed by Star Trek mythology," Showalter explained. "We don't normally associate Vulcan with Pluto, but in fact when you go back to the literature, the Greeks and Romans understood the underworld to encompass everything beneath the surface of the earth, not just the realm of the dead. So Vulcan, the god of lava and volcanoes, really does have a natural connection to underworld.

"That being said, the nomenclature working group has to grapple with the issue that in astronomy, the name Vulcan has previously been associated with a hypothetical object or objects orbiting interior to Mercury. They also will probably have concerns about the fact that Cerberus has already been used as the name of an asteroid. I still believe that it is very important to give the working group latitude in this decision. I remain optimistic that a consensus will emerge."

One possibility would be to use Kerberos as an alternate spelling for Cerberus, to avoid any potential confusion. That's how the discoverers of another moon of Pluto, Nix, got around the fact that there was already an asteroid named after Nyx, the Greek goddess of the night.

Nicknaming an exoplanet

Meanwhile, another celestial naming contest has come to a surprise ending. For weeks, a commercial venture called Uwingu has been running a contest to come up with an unofficial nickname for Alpha Centauri Bb, the closest exoplanet. Thanks to a last-minute surge of vote-buying, the winner of the planet-naming game is "Albertus Alauda."

"I chose this name to honor my grandfather," Jason Lark wrote in his online citation for the name. He explained that Albertus Alauda is the Latin translation of Albert Lark, his grandfather's name.

Uwingu charges $4.99 for each planet nomination, and 99 cents for each vote. A spokeswoman for Uwingu, Ellen Butler, told NBC News in an email Tuesday that Lark "came in with a $742.50 payment last night to take the win." The mass voting is perfectly in accordance with the rules of Uwingu's game.

"I am overjoyed that my nomination won," Lark told NBC News in an email. "I think my grandfather would be very happy, and I hope my citation does him justice. I am very proud of my granddad. As with any other star or planet, they along with their names live on much longer than any one man, and most have a story behind them, such as in the days of old when stars were used to navigate the globe. I would like to think that Albertus Alauda will take its place alongside them in the generations to come, along with the story behind it."

Uwingu was created last year to offer space-based entertainment, to generate revenue and raise money for space science and education projects. The aim is to distribute at least half of the proceeds in the form of grants to programs such as the SETI Institute's Allen Telescope Array, Astronomers Without Borders and the Galileo Teacher Training Program. The contest to nickname Alpha Centauri Bb, which was discovered last year just 4.3 light-years from Earth, brought in about $10,000.

Among the runner-up names were Sagan and Einstein, Ron Paul and Heinlein, Rakhat (the Alpha Centauri planet featured in a sci-fi novel called "The Sparrow"), Tiber (the Alpha Centauri planet that moonwalker Buzz Aldrin made famous in his novel "Encounter With Tiber") and Amara (the first name of the nominator's fiancee). In all, more than 1,200 names were nominated.

Neither Albertus Alauda nor any of those other names has official status with the IAU. In a stinging news release, the IAU said Uwingu's campaigns "will not lead to an officially recognized exoplanet name, despite the price paid or the number of votes accrued."

There is currently no IAU-sanctioned process for approving popular names for the hundreds of extrasolar planets detected beyond our solar system. Instead, astronomers take the name of the star (for example, Alpha Centauri B or Kepler-62) and tack on a letter of the alphabet, starting with "b." (Hence, Alpha Centauri Bb or Kepler-62f.) For the time being, the IAU is sticking with that system, although it said members would discuss establishing a friendlier naming scheme this year.

Meanwhile, Uwingu's "baby book of names" for exoplanets remains open for business. "Also, next week we'll debut a new way to engage in exoplanet naming," Uwingu's CEO, planetary scientist Alan Stern, said in an email.

More about exoplanet names:

Alan Boyle is's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.