How Did Alien Solar System Form? Trappist-1 Planet Pieces Melted Together At Ice-Water Zone

When astronomers first found the Trappist-1 solar system, part of what made the discovery of the seven Earth-sized exoplanets so novel was how unusual it was to find that many planets orbiting their small star so closely, about a tenth of the distance between the Earth and the sun. But scientists may have solved the riddle, attributing the planets’ compact formation to the unique conditions at the star’s “ice line.”