How stars are made?

Formation of stars is an exciting process. Stars are born in nebulas.Nebulas are clouds of dust in interstellar space. An interstellar cloud is usually in hydrostatic equilibrium that means there is a balance between the gravitational force and gas pressure. But if a cloud is dense and cold enough, then the gravitational force would dominate over gas pressure which leads to gravitational collapse of the cloud.PROTOSTAR STAGE- As the cloud continues to collapse, the centre of the clump collapses to a dense, gravitationally stable core known as a protostar which heats up as it continues to contract. The protostar grows by accreting more material from the surrounding molecular cloud, and thus it's core gets denser and hotter. Due to the conservation of angular momentum, this material spirals in towards the star and forms a disk of materials that orbit the star slowly accreting onto the star in bright bursts, thus illuminating the surrounding cloud.NEWLY BORN STAR - With each burst, the star becomes hotter and more massive, a point is reached when the temperature rises so much that nuclear fusion starts taking place. At first, the star can only burn Deuterium, but as it gets hotter, it burns hydrogen just like our own Sun. The star now begins to shine quite brightly, and the radiation from star prevents further material accreting onto the star, and it may even disperse the remaining material in the disk that still surrounds the star.Once the star starts nuclear fusion from hydrogen to helium, we say that the star is born.Hydrogen fusion is a natural source of energy for most of the stars. The stars continue the fusion of lighter to heavier elements until it reaches the atomic number of iron. At this point, repulsive forces are stronger, and fusion becomes an endothermic process requiring energy.Elements heavier than iron are only produced in Supernova explosions. read less

Stars are made up of a cloud of dust and gases like hydrogen and helium which is present in the galaxy in abundance.There is a tug of war between gases pressure and gravity. Gases exert pressure outward, and they try to expand while gravity compresses inward. This process may take millions of year approximately. Lastly, gravity wins, and it turns into a shape like a fireball. After the star has formed, it produces a tremendous amount of heat and light energy due to nuclear fusion reaction of hydrogen gases. read less