Super star cluster

A super star cluster, or SSC, is an extremely massive and young open cluster of stars. These clusters are much more luminous and contain more mass than other young star clusters. Astronomers call them "super" because of this high brightness and heavy mass. While they are very heavy, they do not necessarily have to be physically larger than smaller clusters. Many scientists believe that these clusters are the precursors to globular clusters. This means they may evolve into those types of clusters later in their lifetimes.

The way these clusters interact with their environment is quite intense. An SSC contains a very large number of young, massive stars. These stars emit energy that ionizes the gas surrounding them. This creates a region of ionized hydrogen known as an HII region. In some cases, this is called an ultra dense HII region, or UDHII. This glowing gas is often wrapped in a thick cocoon of dust. This dust causes extinction, which blocks visible light from reaching our telescopes. Because of this, astronomers often use radio and infrared light to see the youngest clusters.

Super star clusters have specific physical properties that define them. They typically have a radius of about 5 parsecs, which is a unit of distance used in space. Their age is often estimated to be around 100 million years. However, some other scientific sources state that observed SSCs may be 1 billion years old. The HII regions associated with these clusters also have very high electron densities. They also exist in environments with very high pressures. These specific traits help astronomers identify them among other types of star groups.

These massive clusters usually form in very active parts of the universe. They are often seen when two galaxies interact or merge together. They also appear in regions with very high star formation rates. These areas must have enough pressure to allow such large clusters to form. You can find them in dwarf starburst galaxies or in the arms of spiral galaxies. In 1996, a study in the Astronomical Journal looked at star-forming rings in five barred galaxies. Using the Hubble Space Telescope, researchers found clusters in clumps within these rings. These clusters had masses of about $10^5$ to $10^6$ solar masses.

Finding these objects has historically been a difficult task for astronomers. Because SSCs are small compared to their host galaxies, they are hard to spot. Older ground-based telescopes lacked the resolution needed to see them clearly. This changed in the 1990s with the introduction of the Hubble Space Telescope. The Hubble has a high angular resolution of about 1/10 arcsecond. This allows scientists to see the clusters and even measure individual stars within them. The telescope helps search nearby galaxies for dense stellar objects that might become globular clusters.

We have discovered several important examples of these clusters in our sky. Bengt Westerlund discovered Westerlund 1 in our Milky Way Galaxy in 1961. This was the very first super star cluster found in our own galaxy. Inside Westerlund 1, astronomers recently found a massive star called Westerlund 1-26. This star is so large that its radius might be greater than Jupiter's orbit. Another famous example is R136, which is considered a prototype SSC. R136 is located inside the NGC 2070 region within the Large Magellanic Cloud.

There are many other clusters that help us understand these systems. In the galaxy M82, the Hubble Space Telescope has identified 197 young SSCs. In the Large Magellanic Cloud, clusters like NGC 2070 and H72.97-69.39 are also studied. Some clusters, like NGC 5253, are very dusty and are sites of ongoing star formation. This specific cluster is very rich in O-type stars, containing at least 7,000 of them. By studying these different types and locations, astronomers learn how the most massive structures in the universe are built.