An Earth-mass Planet Orbiting a Centauri B

摘要

As most astronomers (both amateur and professional) know, the a Centauri system is the closest stellar system to the Sun. Tiny Proxima is a little closer than the main components, a Cen A and B, which lie at a distance of just under 4.4 light years. Xavier Dumusque, of the Geneva Observatory in Switzerland, and his colleagues there and in France and Portugal, have discovered a planet with a mass similar to Earth's orbiting a Cen B (Nature, November 8 issue). The planet is nowhere near the habitable zone-its orbital period is just 3.24 days-but it demonstrates that we are closing in on the ultimate goal: an Earth-like planet in an Earth-like orbit around a Sun-like star.