Population II

The classification given to the older stars within a spiral galaxy (including our own Milky Way) that are thought to predate the formation of the galaxy's spiral structure. By comparison with younger Population I stars, elements heavier than hydrogen or helium are rare in the stars of Population II. These older stars also tend to be redder in colour than their younger counterparts, a factor responsible for the red-yellow colouration of the more central regions of a typical spiral galaxy. Population II stars also predominate in the Globular Clusters that surround the Galactic disc.

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