What will happen to the Sun before the white dwarf stage?

Answer 1

During the Red Giant stage, all the hydrogen of the star will be used up and helium will start to fuse.

Because helium burning reactions are extremely sensitive to temperature, this causes great instability. Massive pulsations build up, which eventually causes the outer layers to be ejected, potentially forming a planetary nebula.

At the center of the nebula remains the core of the star, which will cool down to become a white dwarf.

Answer 2

Nothing. The white dwarf just slowly cools over billions of years.

Answer 3

The sun is too small to form a black hole. It will go from it's current size up to a red giant, then eventually a white dwarf.

Answer 4

The long-term fate of the sun according to current theories in stellar evolution, is to become a white dwarf. It lacks the mass to further collapse into a neutron star or black hole.