Scientists say Earth-sized planet circling sun's closest star may be habitable

PARIS – Scientists Wednesday announced the discovery of an Earth-sized planet orbiting the star nearest our Sun, opening up the glittering prospect of a habitable world that may one day be explored by robots. Named Proxima b, the planet is in a "temperate" zone compatible with the presence of liquid water -- a key ingredient for life. The findings, based on data collected over 16 years, were reported in the peer-reviewed journal Nature. "We have finally succeeded in showing that a small-mass planet, most likely rocky, is orbiting the star closest to our solar system," said co-author Julien Morin, an astrophysicist at the University of Montpellier in southern France. "Proxima b would probably be the first exoplanet visited by a probe made by humans," he told AFP.