# Intro - The Need for Subdivisions Stellar Astrophysicists and astronomers value names a lot, and if given the chance we'd probably remove the ability for people to separate based on attributes. As a result, Stellar Astronomers have decided to separate stars into three populations - Population I, II and III. Even then, the way we determine how to classify stars is counterintuitive, like most things in astronomy... ### How do we classify it? >[!Danger] Reiterating from above, the way we classify stars is counterintuitive. We actually label prehistoric, "precursor" stars as Population III, while the latest generation of stars comes with the label of "Population I". Weird, I know! You'd expect Population I stars to be the first stars in the Universe, but it takes a special sort of brain to decide to delve into astronomy, let alone astronomical research ;) # Population I --> population I stars - all ages - mostly in spiral arms - enriched with heavy elements (1-4% of composition, high metallicity) # Population II - entirely old stars, 11-13 billion years (no young stars) - mostly in bulge and halo - very few heavy elements in the composition # Population III --> no heavy elements --> very old, first stars after the big bang --> very, very far away, going back into time as far as possible --> unconfirmed at the moment