In 2011 and 2012 the group of astronomers by leadership of Mark Showalter discovered two new satellites of Pluto.
These are the forth and fifth satellites of Pluto. The dimensions of P4 are from 13 up to 34 km, and the P5 are form 15 up to 24km. According to rules of the International astronomical union, the satellites have to receive the names from Greek-Roman mythology, which is connected with underground kingdom of Aida. The discovers offered 12 mythology names, and everyone can vote for the name, which likes to him. In the voting totally participated 450 people, from them 174,000 voted for Volcano (the Roman God of underground fire), and 99,400 voted for Cerberus (the three-headed dog guarding a gate of the underground world).
Astronomers noted, that the results of vote have only a consultative role and they didn’t assume the obligation to call the satellites of Pluto as the people voted.