Habitable Zones Around Alien Suns May Depend on Chemistry
Trace elements in stars may influence the evolution of habitable zones around them where life as we know it might dwell. Stars are made nearly entirely from hydrogen and helium gas. Still, traces of heavier elements — which astronomers call metals, even if they are not what one normally think of as metals — can be found in stars as well, either inherited from the remains of older stars or forged via nuclear fusion.
Scientists can detect what elements a star possesses by looking at its light, which comes in a wide variety of wavelengths, some visible, many invisible. The wavelengths of light that matter emits often comes in specific clumps or lines, which can act like a fingerprint, revealing the identity of the material in question.