White dwarf
From Tardis Wiki, the free Doctor Who reference
White dwarfs were small stars that were very dense; the enormous gravity of stars were so much greater than the energy of fusion within them that they collapsed. Dwarf star alloy was gathered from such stars. (TV: Warriors' Gate [+]Loading...["Warriors' Gate (TV story)"], Day of the Moon [+]Loading...["Day of the Moon (TV story)"])
