White dwarf
From Memory Alpha, the free Star Trek reference.
A white dwarf is a star formed when a red giant runs out of helium fuel after losing most of its mass into space.
In 2364, the SS Tsiolkovsky was observing the formation of a white dwarf when its crew succumbed to polywater intoxication. The USS Enterprise-D, sent to investigate, was subsequently threatened by a stellar core fragment thrown off by the collapse of the red giant. (TNG: "The Naked Now")
White dwarfs are the only natural source of vertion particles. In 2370, a network emergent circuit nodes aboard the Enterprise-D collected vertions from the white dwarf Tambor Beta-6 to sustain their growth, but the supply from a single star proved insufficient. (TNG: "Emergence")
