The people have spoken and they have been overruled.
After a team of researchers discovered two previously unknown moons orbiting Pluto in 2011 and 2012, Mark Showalter, the team's leader, decided to turn to the public for a vote on what the new moons ought to be named. When the polls closed in February, more than 450,000 votes were in, and 'Vulcan' was the clear winner, helped in part by a campaign by the man who had proposed it, William Shatner.
Alas, Shatner's dream was not to be. This morning the International Astronomical Union announced the names of the two moons, and it has chosen Kerberos and Styx, the second and third most popular in the vote. On its website, the IAU explained the reason for its countermajoritarian ruling (emphasis added):
To be consistent with the names of the other Pluto satellites, the names had to be picked from classical mythology, in particular with reference to the underworld -- the realm where the souls of the deceased go in the afterlife. The contest concluded with the proposed names Vulcan, Cerberus and Styx ranking first, second and third respectively. Showalter submitted Vulcan and Cerberus to the IAU where the Working Group for Planetary System Nomenclature (WGPSN) and the Committee on Small Body Nomenclature (WGSBN) discussed the names for approval.
However, the name Vulcan had already been used for a hypothetical planet between Mercury and the Sun. Although this planet was found not to exist, the term "vulcanoid" remains attached to any asteroid existing inside the orbit of Mercury, and the name Vulcan could not be accepted for one of Pluto's satellites (also, Vulcan does not fit into the underworld mythological scheme). Instead the third most popular name was chosen -- Styx, the name of the goddess who ruled over the underworld river, also called the Styx.
After a final deliberation, the IAU Working Group for Planetary System Nomenclature and the IAU Committee on Small Body Nomenclature, in charge of naming dwarf planets and their systems, agreed to change Cerberus to Kerberos -- the Greek spelling of the word, to avoid confusion with an asteroid called 1865 Cerberus. According to mythology, Cerberus -- or Kerberos in Greek -- was a many-headed dog that guarded the entrance to the underworld.
Better luck next time, Captain.