Question

What are the 6 stages of how a star is formed?

Answer 1

The stars have several stages in their birth span where they start as gas clouds, leading to the fission reactions taking place at its core but ends up or completes its life span with the collapse of the core, only to convert into a different body like a supernova, white dwarf or a black hole depending on the size.

Complete solution:
Stars also have life span like human beings, they go through birth, growth and changes and ultimately death but the only difference is that the life span of stars follows through millions of years.

The first stage is the birth of a star. A star originates from a gas cloud and the gas cloud is such that the temperature is low enough for the formation of molecules.
The second stage is known as the prostar. The gas molecules have a completely random motion; similarly, in the gas cloud of star due to random motion of gas molecules, they collide with each other and produce heat energy. The heat energy leads to the formation of a cluster of warm gas molecules, which are known as prostar. The prostars are hotter than other molecules and several clusters or prostars can be formed depending on the size of the gas cloud.

The next stage in the lifespan of a star is the T-Tauri stage. A T-Tauri star is formed when the gas molecules can no longer form any prostars and release huge amounts of energy. The mean temperature at the core of Tauri star is not enough to support nuclear fission. The Tauri stage lasts for around 00 million years.

The next stage is the Main Sequence stage. This stage is reached when the temperature at the core is high enough for nuclear fissions to take place. Here, nuclear fissions take place at the core in which the hydrogen is converted into helium and tremendous amounts of energy are released.

When the hydrogen fuel of the star runs out and no more reactions take place at its core, then the star enters into the fifth stage called the Red Giant stage. Due to gravitational pull of the star, it starts to contract inwards causing it to expand. When it expands, it first becomes a subgiant and then a red giant. The Red Giant stars have a coloured surface.

At the sixth stage, as the star continues to expand the helium molecules fuse together. The energy released due to fusion of helium molecules prevents the core of the star from collapsing. When helium fusion ends, the core starts fusing carbon molecules giving rise to formation of iron which then undergoes fusion. The iron fusion absorbs energy which ultimately leads to the collapse of the star. This leads to massive stars converting into a supernova or the smaller stars like the sun to convert into white dwarfs.

Note:
Some stars that we see in the sky might have been dead as stars are so far away from each other that by the time there light reaches us, their lifespan completes. Sun is one of the average sized stars and is currently in the Main Sequence life stage. After its collapse, it will convert into a white dwarf star. A white dwarf star is a star with a leftover core which is much hotter and denser.