Population II stars spread
A second generation of stars, built from the ashes of the first, fills the young galaxies.
- When
- Known to
- ± 500 million years
- Era
- Reionisation, Stelliferous
Stars forming from gas already enriched by the first supernovae carry small but measurable amounts of heavier elements. They are long-lived, and many are still burning today in the halo and globular clusters of the Milky Way — which makes them readable records of the chemistry of the early universe. The most metal-poor of them are the closest thing we have to a direct sample of the first stars' output.