The Centaurian System

Poul Anderson, Harvest Of Stars, 40.

Alpha Centauri A and B are in orbit around each other;

Proxima, a red dwarf, discovered telescopically, is on a wider orbit;

(Beta Centauri, elsewhere in Centaurus, is the second brightest star in the constellation);

A had three planets but captured Phaeton from B;

A's outermost planet, Demeter, bears life;

B had two planets but lost Phaeton;

between A and B is the forbidden zone of chaotically orbiting asteroids;

Phaeton passed through the forbidden zone and now orbits A on retrograde comet-like ellipses that will make it collide with Demeter in a thousand years;

human beings will colonize Demeter;

Lunarians led by Rinndalir will colonize the Centaurian asteroids rather than staying in the Solar System where social evolution is not to their liking.