How Stars Are Born: A Cosmic Journey

As the cloud continues to contract, its central region becomes increasingly dense and hot.This central core, now called a protostar, continues to grow as surrounding material falls inward.As material falls onto the protostar, gravitational energy converts to heat, dramatically increasing its temperature.A disk of gas and dust forms around the protostar due to conservation of angular momentum.During this phase, the protostar remains hidden within a thick envelope of dust, making it invisible to optical telescopes.However, we can observe protostars using infrared light, which can penetrate through the dust envelope.As the protostar continues to contract and heat up, its core temperature rises dramatically.When the core temperature reaches fifteen million degrees Celsius, conditions become perfect for nuclear fusion to begin.In the fusion process, four hydrogen atoms combine to form one helium atom, releasing an enormous amount of energy.In a main sequence star, the outward pressure from nuclear fusion perfectly balances the inward pull of gravity, creating a stable state.The star's mass determines how long it will remain in this stable state. Less massive stars live longer, while more massive stars burn through their fuel more quickly.