habitable planets

[Little lunch]

There's a moon of Saturn called Enceladus.
It has an ocean of liquid water with an ice crust.
As Cassini passed by it detected hydrogen being pushed out into space, which could mean oxygen exists there also.
It's not very big though.
Here on Earth, if we stopped war and spent our money on research, we could possibly find a way to stop the aging process and live here for roughly 10 billion years.

10 billion years?   The earth will either be swallowed or burnt to semi-molten slag when the sun goes red giant in half that time.

But Given that a star’s life span increases exponentially with decreasing mass,  I suppose it is conceivable a plant around a dimmest and least massive main sequence red dwarf star can stay in the habitable zone for 10 trillion years.

I said roughly. :-)