From "The case of the missing neutrino" by John Gribbon, written in
1997, our sun would turn into a white dwarf after death. From "Parallel
worlds" by Michio Kaku, written in 2005, our sun would turn into a red
giant after death.

Which one is correct? Or are both cases possible? Or white dwarf was a
previous theory while red giant is a more recent one?