In order to understand the structures of various stars, it is important to understand the different forces that work with and against each other during the lifetime of a star. The two most important forces that define a star’s life are fusion and gravity. Gravity pulls the mass of a star inward, heating and pressurizing the core of a star to tremendous levels. The early formation of all stars is dominated by gravitational collapse. Very young stars glow not from fusion in their cores, but from gasses glowing from the immense temperature generated by gravitational pressure. If a collapsing mass of gas is large enough, the pressure and temperature of the core will exceed the conditions needed to overcome the electrostatic repulsion between atoms, allowing the nuclei of atoms to come in direct contact with each other. This process of atomic collision is know as fusion and is responsible for the energy output of stars once they have passed their gravitational collapse stage of life.
The outward pressure of the energy released by the fusion process directly opposes the inward pull of gravity, creating a state of equilibrium for the star that lasts as long as fusible material exists within the core of the star. These two opposing forces define the life and death of all stars. The deciding factor of the nature of a star’s existence is the initial mass of the star. Depending on the total mass of a star, it can live for trillions of years, burn brighter than a thousand suns, or collapse into an inescapable singularity. I will be exploring how and why these reactions take place within stars while exploring the birth and death of each type of star.