Stellar Astronomy: Part 8 – Stellar Clusters and Populations

Stars often exist as binary pairs – two or more stars that orbit their common center of mass.  However, even larger numbers of stars can exist in close proximity to each other – a star cluster – which can consist of hundreds to hundreds of thousands of stars.  Single stars, binaries, and star clusters exist as part of a much larger structure – a galaxy – which can contain millions to trillions of stars.  Furthermore, the composition of stars varies slightly in a way that depends on where they are found.