What Are Star Clusters?

A star cluster is a group of stars with more than 10 stars and physical connections (gravitation). Loosely structured and irregularly-shaped star clusters, consisting of a dozen to hundreds of thousands of stars , are called scattered clusters. They are mainly distributed on the galactic plane and are also called galactic clusters. Also known as the Pleiades star cluster); consisting of tens of thousands to hundreds of thousands of stars, the whole is like a circle, and the densely clustered star clusters are called globular clusters.

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Globular clusters are

Star clusters are usually named using the corresponding star list. The most commonly used are

Open clusters: Loosely structured, irregularly-shaped star clusters consisting of a dozen to a few thousand stars, mainly distributed in

Once an open star cluster is not constrained by gravity, the formed stars will continue to move in space on similar paths. Such groups are called star associations or moving constellations. in

Corresponding to open clusters such as the Aung Su cluster, the other half of the star cluster family-globular clusters.

Some member stars of the Milky Way star cluster have similar self-velocities and directions, and tend to scatter from a radiation point or converge toward a convergence point. This type of star cluster that can determine the point of radiation or convergence is called

Star clusters are important in many areas of astronomy. Because stars are born at about the same time, and the star functions in the same group are only different in mass, the theory of stellar evolution relies entirely on observations of open clusters and globular clusters.

Star clusters are also a crucial step on the cosmic distance scale. There are several closest clusters, and distances can be measured using parallax, and the absolute magnitude of known stars in these clusters can be plotted on the Hero chart's brightness axis. Then, after drawing a Hero chart of an unknown distance cluster, the distance of the cluster can be estimated by comparing the position of the main sequence band. This procedure is called main-sequence fitting, and the effects of reddening and star family should be considered when using this method.