Editing Stellar population (section)

===Formation of the observed stars===

The oldest stars observed thus far,<ref name=Schlaufman-Thompson-Casey-2018/> known as population&nbsp;II, have very low metallicities;<ref name=Salvaterra-Ferrara-Schneider-2004/><ref name=Byant-2005/> as subsequent generations of stars were born, they became more metal-enriched, as the [[gas]]eous clouds from which they formed received the metal-rich [[cosmic dust|dust]] manufactured by previous generations of stars from population&nbsp;III.

As those population&nbsp;II stars died, they returned metal-enriched material to the [[interstellar medium]] via [[planetary nebula]]e and supernovae, enriching further the nebulae, out of which the newer stars formed. These youngest stars, including the [[Sun]], therefore have the highest metal content, and are known as population&nbsp;I stars.