What if we could determine if a given star is likely to host a planetary system like our own by breaking down its light into a single high-resolution spectrum and analyzing it? A spectrum taken of the Sun is shown above. The dark bands result from specific chemical elements in the star’s outer layer, like hydrogen or iron, absorbing specific frequencies of light. By carefully measuring the width of each dark band, astronomers can determine just how much hydrogen, iron, calcium, and other elements are present in a distant star. The new model suggests that a G-class star with levels of refractory elements like aluminum, silicon, and iron significantly higher than those in the Sun may not have any Earth-like planets because it has swallowed them.
N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF