Csillagpopulációkat

Csillagpopulációkat, often translated as stellar populations, refers to groups of stars that share common origin and evolutionary history. These populations are distinguished by their chemical composition, specifically the abundance of elements heavier than helium, known as metallicity, and their location within a galaxy. The oldest stars in a galaxy are typically found in the halo and globular clusters, and they exhibit very low metallicity. These are designated as Population II stars. They formed early in the universe's history when heavy elements were scarce, as these elements are produced in stars and dispersed through supernovae.

In contrast, younger stars are generally found in the galactic disk and spiral arms. These are classified as Population I stars. They have higher metallicities because they formed from gas and dust clouds that were enriched by previous generations of stars. A third, less common, theoretical population, Population III, is hypothesized to consist of the very first stars in the universe. These would have been composed solely of hydrogen and helium, with no heavy elements. Studying stellar populations helps astronomers understand the formation and evolution of galaxies, including the timeline of star formation and the chemical enrichment processes that have occurred over cosmic time.