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.
Astronomers have discovered a roughly Earth-size alien world around Proxima Centauri, which lies just 4.2 light-years from our own solar system. What’s even more exciting, study team members said, is that the planet, known as Proxima b, circles in the star’s “habitable zone” — the range of distances at which liquid water could be stable on a world’s surface.
“The key question of our initiative was whether there were potentially life-bearing planets orbiting these stars. We know now there is at least one planet with some characteristics similar to the Earth,” said Pete Worden, a former top NASA manager, who was speaking at a European Southern Observatory webcast news conference to announce the find.
Proxima b orbits its parent star every 11 days. Because of the method used to detect it,we don’t actually know how massive the planet candidate is – but we can say with confidence that it’s at least 1.3 times as massive as the Earth. It’s just over 4 million miles away from its cool, tiny red dwarf of a star (much closer than we are to our own sun), so it is blasted with enough radiation to maintain a balmy surface temperature of around minus 40 degrees Fahrenheit.
Astronomers have been hunting intensively for planets around Proxima Centauri for more 15 years, using instruments such as the Ultraviolet and Visual Echelle Spectrograph (UVES) and the High Accuracy Radial velocity Planet Searcher (HARPS), both of which are installed on telescopes run by the European Southern Observatory in Chile.