Star Clusters

Star clusters are groups of stars that are gravitationally bound and have formed together from the same molecular cloud. They are broadly categorized into two main types:

1. Open Clusters:

   • Characteristics: Contain a few dozen to several thousand stars. They are loosely bound and often irregular in shape.

   • Age and Composition: Typically young, with ages ranging from a few million to a few billion years. They predominantly consist of Population I stars, which are rich in metals.

   • Location: Found primarily in the spiral arms of galaxies, including the Milky Way.

   • Examples: The Pleiades and Hyades clusters in the constellation Taurus.

2. Globular Clusters:

   • Characteristics: Densely packed, spherical collections containing tens of thousands to millions of stars.

   • Age and Composition: Among the oldest known stellar systems, with ages around 10 to 13 billion years. They consist mainly of Population II stars, which have low metal content.

   • Location: Reside in the halos of galaxies, orbiting the galactic core.

   • Examples: Omega Centauri and 47 Tucanae.

Studying star clusters provides valuable insights into stellar evolution, as the stars within a cluster are formed around the same time and at similar distances from Earth. This uniformity allows astronomers to test theories of stellar development and understand the dynamics of star formation.

Now read the following section from OpenStax Astronomy.