Pluto
From Tardis Wiki, the free Doctor Who reference
Pluto or Sol IX is one of the outer planets of the Sol system. Pluto is extremely far from the sun and its unusual orbit takes it out into the Kuiper Belt, but occasionally closer to the sun than Neptune. It became Humanity's new home after Earth's resources were exhausted. These remaining Humans were shipped to Pluto by the Usurians, and 6 artificial suns were placed around Pluto. (DW: The Sun Makers)