History of Star formation: 

According to the International Astronomical Union, stars have played an important role in religion and navigation from the dawn of recorded civilization. Astronomy, or the study of the heavens, is one of the oldest disciplines. 

In the 17th century, the advent of the telescope and the discovery of the laws of motion and gravity led to the conclusion that stars, like the sun, obeyed the same physical laws. Photography and spectroscopy made it feasible to study the compositions and motions of stars from afar in the nineteenth century, resulting in the birth of astrophysics.

Stages of Star formation:

1. Nebula: Dust and gases, chiefly hydrogen and helium, make up nebulae. The gravitational pull of clumps of dust and gas aggregates grows stronger as they grow larger. The cluster of dust and gas eventually becomes so large and then its core heats up as it collapses, and this hot core is the start of a star.
2. Protostar: A protostar consists of a slowly revolving center star, a disc encircling it, and an opaque envelope of collapsing material that accretes largely onto the disc during a typical stage of its formation.
3. T-Tauri: Still engulfed in its natal molecular cloud, the protostar is accreting fresh material and forming a proto-planetary disc. The surrounding shell of gas and dust is slowly blown away by stellar winds and radiation, and the third stage, after the surrounding envelope has cleared, is known as the T-Tauri phase.
4. Main Sequence: A main sequence star is one that is in the middle of its life cycle and is steady. They are the most prevalent star type in the universe. The Sun, our star, is in the main sequence. It’s about halfway through this stage, and in about five billion years, it’ll turn into a red giant.
5. Red-giant: At its center, a star transforms hydrogen atoms into helium over the course of its existence, and when hydrogen fuel runs out the core expands turning it into a red giant.
6. Undergoing Fusion: After helium fusion completion, the core begins fusing carbon until the iron element is further found in it. Thus, the iron fusion event absorbs all the energy which results in the core collapse.
7. Planetary nebulae and Supernovae: The outer layers of the star are blasted into space, but the center implodes into a neutron star or a singularity known as a black hole.

Constellation: 

Constellations are not real because they are made up of a group of stars that form an imaginative shape in the night sky. They are generally given names based on legendary figures, people, animals, and objects.

• People in various places of the world have created various shapes out of the same clusters of brilliant stars. It’s similar to a dot-connecting game.
• Creating fictional images out of stars was once a vital tool for night navigation and keeping track of the seasons.
• Because all of the stars are at various distances from each other, the constellations would seem to people of another planet orbiting another star to be completely different.

Some major examples of constellations are Ursa Major, Orion, Hydra, and Cygnus.

End states of Stars: 

• The star’s stretched outer envelope wanders off into space in most cases, especially among low-mass stars, while the core cools down as a white dwarf.
• When the remaining core’s mass reaches between 1.4 and 2 solar masses, it seems to become a neutron star with a mass more than a million times that of a white dwarf.
• The collapsing star’s gravitational field is expected to be so powerful that neither matter nor light will be able to escape it which will form a black hole after collapsing.