New Earths? Alpha Centauri consists of 3 stars. Though no planets have yet been detected, it is still possible that a number of non-Jovian worlds exist there. Alpha Centauri AB The inner pair of stars, "AB," have an eccentric orbit making the formation of planets less likely, though not impossible. The eco-zone for each sub-system is significantly smaller than the periastron, or closest approach, between the two stars. It is uncertain, though, if the distance is great enough for planets in each sub-system to maintain stable orbits.

Alpha Cen A The main star is bright enough that its eco-zone is safely distant from its tidal braking zone.

Alpha Cen B The system's secondary star is a borderline candidate for habitable worlds. Part of the eco-zone straddles the outer portion of the tidal braking zone. A planet within the tidal braking area would likely not be able to maintain a healthy night-day rotation.

Alpha Cen C Two factors make Proxima Centauri a poor prospect for even one habitable world. First, the star's eco-zone is embedded deep within the tidal braking zone. Any planet close enough to garner Earth-like warmth would long ago have stopped its rotation — one side forever in daylight, the other in perpetual night. Second, Proxima is infamous as a "flare" star, with wide and unpredictable fluctuations in energy output. Even if such a world had a close moon to tug the planet into a healthy rotation, the unsteady sunshine would wreck havoc on the weather.