Formation of Stars
The formation of stars is a complex process that occurs within large clouds of gas and dust called nebulae. This process typically involves several stages:
Step 1: Nebula Collapse
– These nebulae are composed mainly of hydrogen gas and dust particles.
– Due to gravitational forces, the nebula begins to collapse inward.
– As the cloud contracts, its density increases, and the gravitational pull becomes stronger.
Step 2: Protostar Formation
– The collapsing nebula spins faster as it contracts, forming a rotating disc of gas and dust.
– At the center of the disc, a hot, dense core called a protostar begins to form.
– The protostar continues to accumulate matter from the surrounding disc.
Step 3: Nuclear Fusion Begins
– As the protostar gains more mass, its core becomes denser and hotter.
– When the temperature reaches around 10 million degrees Celsius, nuclear fusion begins.
– Hydrogen atoms start fusing together to form helium, releasing tremendous amounts of energy.
Step 4: Main Sequence Star
– Once nuclear fusion begins, the outward pressure from the energy released balances the inward gravitational pull.
– The star has now reached the main sequence stage, where it will spend most of its life.
– The star’s color, temperature, and brightness depend on its mass.
Step 5: Star’s Life Cycle
– Stars continue fusing hydrogen into helium for millions or billions of years, depending on their mass.
– When the hydrogen fuel runs out, the star’s life cycle enters its final stages, leading to different possible outcomes based on its mass.
Formation of Star, Planet and Solar System Class 11 Notes
The Universe is a vast expanse filled with celestial bodies, each with its unique formation process and characteristics. From stars that illuminate the cosmos to planets that orbit around them, understanding their origins and evolution is a captivating field of study. This text delves into the intricate processes that give rise to these celestial wonders, shedding light on the theories and mechanisms that shape our cosmic neighborhood.
Let us learn in detail about the formation of stars, planets, and solar system!
Formation of Star, Planet and Solar System Class 11 Notes