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Introduction:

Stars are born in dense, violent nurseries which are typically characterized by activity bursts and interstellar shock waves. Our Sun and Solar System survived 4.5 billion years ago in such a violent environment. The majority of the stars in our immediate cosmic neighborhood most likely formed in a dense cloud of gas and dust. Accompanied by massive stars that died out a long time ago, as well as bright emission nebulae in the neighborhood that were stimulated by these bright stars.

The life cycle of Stars:

  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.

Solar system:

A thick interstellar cloud formed our solar system around 4.5 billion years ago. That cloud disintegrated because of the shockwave produced by a nearby supernova A solar nebula while spinning emerged when this dust cloud imploded. The gravitational pull became so strong that hydrogen atoms started to combine to produce helium, resulting in a massive amount of heat and energy. Thus, the Sun was formed. 

The clumps left further in the disc started clumping together to form spheres by gravity and came to be known as moons, dwarf planets, and planets such as earth, mars, etc. Thus, our solar system was formed with elliptical orbits. Asteroids, comets, meteoroids, and small, irregular moons were left as the remnants.

Star and Planet Formation:

Gas and dust clouds are very common, and we know of many star formation regions in our Milky Way Galaxy. As the gas and dust clouds contract, small condensation centers form, eventually forming new stars. The entire process takes millions of years, but that is a relatively short period of time for changes to occur in space.

When stars evolve, there is always some stuff leftover around the star, which creates a disc around the rotating star’s equator. In a disc, this matter can also condense into gaseous or solid forms. These are known as planetesimals, and they form over a longer period of time than the central star around which they orbit. These planetesimals eventually draw more of the disk’s debris and contract even further to a spherical shape under their own gravity. They establish a system of planets similar to our solar system at this phase.

Death of a star:

  • White Dwarf: 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.
  • Neutron star: When a massive star explodes as a supernova, the core of the star can collapse, resulting in a tiny, superdense object with a mass similar to that of our sun. Neutron stars are the tiny, highly dense cores of exploding stars.
  • Blackhole: 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.

Conclusion: 

Comets, asteroids, and meteorites, as we’ve seen, are surviving remains of the events that generated the solar system. Planets, moons, and the Sun are all products of the formation process, though the material in them has undergone a variety of transformations.