Star Cycle: From Birth To Death

When gas pressure inside the star equals gravity, the star attains a stable state and begins entering the main sequence phase. It attains a temperature of about 15,000,000 °C. Nuclear fusion occurs and it begins to glow. The star contracts and becomes stable.

It is now called the main sequence star or stable star. Stable stars exhibit the condition of equilibrium. Equilibrium is achieved when the force pushing out from the center equals the gravitational force that pulls the atoms inward. As the stars contract, the temperature, density and pressure at the core continue to rise. For a major part of its life span, a star stays in its main sequence phase. The conversion of hydrogen to helium takes place during this stage in the life cycle of a star.