Styx and Kerberos: these are the names the International Astronomical Union (IAU) gave to the two Pluto's moons, discovered between 2011 and 2012, and provisionally called P4 and P5. The final choice has been made after a selection carried out by the international organization on the results of a survey promoted by SETI, to whom everybody could participate.

Such an idea was suggested by Mark Showalter, leader of the team that discovered the two moons with the Hubble Space Telescope (thanks to a NASA-ESA collaboration), and narrowed the range of possible names to those coming from classic Greek-Roman mythology, with a particular focus to Hades names, to be coherent with the other three moons. Styx and Kerberos had the best of the 21 names on the final list, doing better than others like Volcano, Persephone or Orpheus. 

Volcano, in particular, got the highest numbers - also thanks to an excellent backer like the actor William shatner, from the science-fiction tv shows Star Trek, who supported this name as the one that gave birth to Captain Spock - but the IAU could not validate it: it has been already used for an hypothetical planet, whose existence within the Solar System was theorized by Urban Le Verrier in 1859.

Following the discovery of a new celestial body, it is up to the IAU to coordinate each step of the attribution of a name, in collaboration with the Committee on Small Body Nomenclature and the Working Group for Planetary System Nomenclature, together with the free and open participation of astronomers and, sometimes, even of the pubblic. Always abiding by a standard procedure.