A PG 1159 star (aka pre-degenerate) is white dwarf coming into being (or a pre-white dwarf), having completed a planetary nebula phase. The term is coined from the first identified, PG 1159-035, which appears to have resumed helium burning but is expected to cool into a white dwarf. They are hot, in the 75,000-200,000 K and show an excess of ultraviolet. Some characteristics of PG 1159-035:
This is exceptional for being both far smaller and far more luminous than the Sun.