re: Gliese 710
Huh?
What's the crack about Red Giant expansion? That's not going to happen for 7 billion years, whereas Gl710 will flyby in just 1.36 million. And plenty of other stars will near-miss the Oort Cloud in those gigayears before the Sun hits the Red Giant Branch. Plenty of opportunities for a mass exodus of the Solar System via solar sails once the luminosity begins climbing.
Adam