Habitable planet found in solar system next door

Paris, Aug 24 (AFP) Scientists today announced thediscovery of an Earth-sized planet orbiting the star nearestour Sun, opening up the glittering prospect of a habitableworld that may one day be explored by robots. Named Proxima b, the planet is in a "temperate" zonecompatible with the presence of liquid water — a keyingredient for life. The findings, based on data collected over 16 years, werereported in the peer-reviewed journal Nature. "We have finally succeeded in showing that a small-massplanet, most likely rocky, is orbiting the star closest to oursolar system," said co-author Julien Morin, an astrophysicistat the University of Montpellier in southern France. "Proxima b would probably be the first exoplanet visitedby a probe made by humans," he told AFP. An exoplanet is any planet outside our Solar System. Lead author Guillem Anglada-Escude, an astronomer atQueen Mary University London, described the find as the"experience of a lifetime". Working with European Southern Observatory telescopes inthe north Chilean desert, his team used the so-called Dopplermethod to detect Proxima b and describe its properties. The professional star-gazers spent 60 consecutive daysearlier this year looking for signs of gravitational pull onits host star, Proxima Centauri. Regular shifts in the star’s light spectrum — repeatingevery 11.2 days — gave a tantalising clue. They revealed that the star alternately moved towards andaway from our Solar System at the pace of a leisurely stroll,about five kilometres (three miles) per hour. After cross-checking an inconclusive 2000-2014 datasetand eliminating other possible causes, the researchersdetermined that the tug of an orbiting planet was responsiblefor this tiny to-and-fro. "Statistically, there is no doubt," Anglada-Escude toldjournalists in a briefing. "We have found a planet around Proxima Centauri." Proxima b is a mere four light years from the SolarSystem, meaning that it is essentially in our back yard onthe scale of our galaxy, the Milky Way. It has a mass around 1.3 times that of Earth, and orbitsabout seven million kilometres (4.35 million miles) from itsstar. A planet so near to our Sun — 21 times closer than Earth– would be an unlivable white-hot ball of fire. But Proxima Centauri is a so-called red dwarf, meaning astar that burns at a lower temperature.(AFP)APK