Structure of Gravitationally Bound Stellar Groupings

Structure of Gravitationally Bound Stellar Groupings

Overview

  • Gravitationally bound stellar groupings refer to clusters of stars bound by the gravitational pull of their combined mass.
  • These groupings include binary star systems, multiple star systems, open star clusters, globular clusters and galaxies.

Binary and Multiple Star Systems

  • Binary star systems consist of two stars orbiting around their common centre of mass.
  • When more than two stars are involved, the system is called a multiple star system.
  • These systems may reveal their nature by gravitational lensing, in which the gravity of the closer star bends the light of the more distant star.

Open Star Clusters

  • An open star cluster, also known as a galactic cluster, is a grouping of tens to thousands of stars.
  • These stars are gravitationally bound and were formed from the same giant molecular cloud.
  • The most famous example of an open star cluster is the Pleiades or “Seven Sisters”.

Globular Clusters

  • A globular cluster is a spherical collection of stars that orbits a galactic core.
  • These clusters contain tens to hundreds of thousands of stars and are notably more tightly bound compared to open star clusters.
  • Globular clusters can be found in halo regions around galaxies, suggesting they are older structures.

Galaxies

  • A galaxy refers to a vast system consisting of billions of stars, interstellar gas, dust, and dark matter.
  • A variety of galaxies exist, including spiral galaxies, elliptical galaxies and irregular galaxies.
  • Our solar system resides in the Milky Way galaxy, which is a spiral galaxy.
  • Some galaxies form clusters known as galaxy clusters.

Importance of Understanding Stellar Groupings

  • The study of these groupings provides insight into stellar evolution, as stars within the same cluster are generally of similar ages.
  • Observation and analysis of these groupings also provide crucial evidence for the Big Bang theory and offer perspective on the scale and structure of the cosmos.
  • Technological advances continue to improve our understanding of these star groupings and how they form, evolve, and eventually dissipate.