A young red dwarf can look calm from a distance. But buried in its light may be the chemical remains of a wrecked world. That is the picture emerging from a new analysis of stars in open clusters, where astronomers found some of the clearest evidence yet that certain young stars may swallow nearby rocky planets. The clue is lithium, a fragile element that should vanish early in these small stars, yet in a handful of cases is still sitting in plain view. The stars in question are red dwarfs, the smallest and coolest stars in the universe, and by far the most common. They are dim compared with the Sun, but their interiors run hot enough to destroy lithium soon after they form. That makes any later detection of lithium stand out sharply. “We found that a few of the red dwarf stars we studied contained lithium, a chemical element that should not be there,” lead author Professor Robin Jeffries of Keele University said. “Therefore even a small amount of lithium stands out clearly …