 The public could choose from a selection of Greek mythological names related to the god Pluto, or could propose their own names.After the initial announcement, William Shatner, the actor who played Captain James T. Kirk in the "Star Trek" franchise, proposed the names Vulcan and Romulus, ostensibly referring to the fire god Vulcan (a nephew of Pluto), and to Romulus the founder of Rome, but also alluding to the fictional planets of Vulcan and Romulus in the "Star Trek" universe.The 'Romulus' suggestion was discounted, because there is already an asteroid moon of that name, but Vulcan won the poll after Shatner tweeted about it, with Cerberus (the dog that guards Pluto's underworld) coming second and Styx (the goddess of the river of the underworld) coming third.