Only stars like our sun, a heavy metal star can breed planets like Earth with an iron-nickel core. Here is one with five planets, one in a habitable zone, only 12 light years away. If inhabited SETI should have picked up signals by now:-"At a distance of twelve light years and visible with the naked eye in the evening sky, Tau Ceti is the closest single star that has the same spectral classification as our Sun. Its five planets are estimated to have masses between two and six times the mass of Earth -- making it the lowest-mass planetary system yet detected. One of the planets lies in the habitable zone of the star and has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of any Sun-like star."-http://www.sciencedaily.com/releases/2012/12/121219084102.htm-http://phys.org/news/2012-12-tau-ceti-sun-like-star-twelve.html