I'd imagine something like the Anarres/Urras double planet system described by Ursula K Le Guin in The Dispossessed (one of my favourite novels) - https://en.wi

I'd imagine something like the Anarres/Urras double planet system described by Ursula K Le Guin in The Dispossessed (one of my favourite novels) - https://en.wikipedia.org/wiki/The_Dispossessed https://en.wikipedia.org/wiki/The_Dispossessed