Globular clusters, open clusters, and super star clusters are all types of stellar associations, but they differ in various ways. Here's an overview of each type:
Globular Clusters: Globular clusters are large, spherical collections of stars that typically contain hundreds of thousands to millions of stars. They are bound together by gravity and are found in the outer regions of galaxies, such as our Milky Way. Globular clusters are usually very old, with ages typically exceeding 10 billion years. The stars in globular clusters are densely packed and gravitationally bound, resulting in a compact, symmetrical shape. The stars within globular clusters are generally old, low-mass stars.
Open Clusters: Open clusters, also known as galactic clusters or stellar associations, are relatively young and contain a few dozen to a few thousand stars. They are typically found in the spiral arms of galaxies, including the Milky Way. Open clusters are less dense and less tightly bound than globular clusters. The stars in open clusters are loosely distributed and often spread out over a larger area of the sky. Open clusters are generally younger than globular clusters, with ages ranging from a few million to a few hundred million years. They contain stars of various masses, including both low-mass and high-mass stars.
Super Star Clusters: Super star clusters, also referred to as young massive clusters, are extremely compact and dense associations of very young stars. They are often found in regions of active star formation, such as in the cores of galaxies or in starburst regions. Super star clusters can contain thousands to millions of stars, and their masses can rival those of globular clusters. They are much more massive and luminous than open clusters. Super star clusters are relatively short-lived compared to globular clusters and open clusters, with ages typically ranging from a few million to a few hundred million years. The stars in super star clusters include high-mass stars, which are responsible for their intense radiation and energetic stellar winds.
In summary, globular clusters are old, spherical collections of hundreds of thousands to millions of stars. Open clusters are younger, less dense, and contain a few dozen to a few thousand stars. Super star clusters are even younger, extremely dense, and can contain thousands to millions of stars, often found in regions of active star formation.