Metallicity

Metallicity refers to the abundance of elements heavier than hydrogen and helium in a star, galaxy, or celestial object. In astronomy, "metals" include all elements except for the lightest two. Metallicity is important because it influences the formation, evolution, and characteristics of stars and galaxies. For instance, higher metallicity can lead to more complex structures and can affect the likelihood of planet formation. Scientists measure metallicity to understand the history and age of celestial bodies, as older stars tend to have lower metallicity due to earlier cosmic conditions.