Thursday, June 20, 2019
What is a star cluster / star group?
There are 200 billion to 2 trillion galaxies in the universe that we can see. Our own Milky Way galaxy itself has about 300 billion stars. The total number of stars in the universe is unimaginable. Most of these stars are wandering like a banner alone. But some of these stars have been living with a companion star or with multiple stars as a family. But apart from these two conditions there are also stars which are in groups of stars in different sizes and numbers. The groups of these stars are bound together in the bond of gravity and they are called star cluster / star cluster. The most striking fact associated with these star cluster is that the relative speed of all their stars is the same, even if there is no movement of other stars around them. |
| Star cluster |
Types of Star cluster
Depending on the physical properties of their stellar substances with the shape, shape and galactic distribution and number of galaxies, stars can be placed in two different categories, which are galactic clusters and globular clusters.Galactic Star Group or Open Star Group (Galactic / Open)
The galaxy star group is also called an open star group. Their member wires can be easily seen separately with the help of a telescope, which is called the open star group. These are usually smaller in size, their stars are spread in a flat shape, and they are distributed in the replica of the galaxy or near the front. There is a few thousand stars in a single open star group that make a huge stellar Molecular Cloud. The age of these stars and the chemical structure are generally the same. The number of stars in these groups ranges from a few dozen to a few thousand.The swell stellata group is only found in spiral curves and irregular galaxies, which are actively forming new stars. In these star groups, the stars are bound from one another to a weak gravitational bond. These star clusters revolve around the galaxy center together and during these visits, the other objects of the galaxy also get scattered through the gravitational influence. The Khalu tara group is relatively new. Its stars come in class I because they are young and more metallic. Its most famous example is The Hyades and Kritika Tarapung (The Pleiades).
Globular Star Group
From the galactic star group to the circular star group, several thousand stars have 10 million stars in a circular form tied with gravity. Our own galaxy has 200 circular star clusters in the galaxy, this star group is in the halo surrounding the replica of the galaxy, these star clusters are the oldest stars in the galaxy. The stars of these star clusters differ from stars of the galaxy star group and the population is of Class II and their metallicity is low and these stars are way ahead in their life order.The amount of free gas and dust in the spherical star group is negligible, these groups do not produce new wires. The density of stars in the inner regions of these circular star groups is high. The stars of the spherical star group, unlike the galactic star groups, do not split on their journey due to the strong gravity tied. Examples of this star group are M56, M15 and Omega Centauri.
Some other types of Star cluster
In addition to these two basic categories, another star group is developing class in the universe. This star group has been called OB Association. This star group contains OB stars, which are in the spectrum of O class and the initial B square and they live in a lightly organized group. The age of these stars is low, so that they can not go far beyond their birth place during their lifetime. But in their brief life span they emit ultraviolet radiation. This radiation ionizes the vast molecular cloud of interstellar gas surrounding it and HII region is formed.In 2005, astronomers discovered a new type of star group in the nearby Andromeda galaxy. This star group keeps the parallelism from the circular star group. But its density is relatively low and the size is very high, which can be several hundred light years. In the Andromeda galaxy, there are three star groups seen in M31WFS C1, M31WFS C2 and M31WFS C3.