Location from remembrance-of-earths-past by
The single planet of the Alpha Centauri three-body system — homeworld of the Trisolarans, hurled from sun to sun by chaotic gravity, destroyed in the Broadcast Era by a dark-forest photoid that gouged its primary star.
Trisolaris is the alien protagonist's hell-home. Civilizations rise and fall there hundreds of times — the wiki numbers them, all the way to Civilization 200, the one that finds Earth's signal. Stable Eras are brief and adored. Chaotic Eras kill almost everyone almost every time. The planet is destroyed in the trilogy's middle act by a single relativistic projectile thrown by an unseen civilization that read humanity's broadcast and acted on it without comment.
A terrestrial world somewhat like Earth in chemistry but never in climate, with a vast moon torn from its own crust by a previous close passage of all three suns. The sky changes color and number of suns from one day to the next. Mountain ranges flash-frozen on one face, melted on the other. Cities flat to the ground, ready to dehydrate at a moment's warning.