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A white dwarf.A white dwarf.A white dwarf.A white dwarf.
A white dwarf could not become a red dwarf. A white dwarf is a remnant of a dead star. A red dwarf is a star with a very low mass.
No in the life cycle of a star, a white dwarf can cool and become a black dwarf
A cooled white dwarf is a black dwarf.
I think you are thinking of a neutron star which has nothing to do with a white dwarf.
Pluto is not a white dwarf star, it is just a dwarf planet.