For how long can the new habitable zone around the Sun's future white dwarf remnant remain stable?

Answer

Billions of years

The remnant left after the red giant phase, the white dwarf, establishes a new habitable zone that can remain stable for billions of years, rivaling the longevity of the star's main sequence phase.

For how long can the new habitable zone around the Sun's future white dwarf remnant remain stable?
astronomylifespanstarred giantstar evolution