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Stellar Evolution Discussed

Discuss stellar evolution. What forces are opposing one another throughout the life of a star and how do they influence the various stages in the life cycle of a star?

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Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity. Stars begin by condensing out of nebular material. As it collapses under the force of gravity it becomes hotter. Stars begin their lives by burning hydrogen in their cores. The product of this burning is helium. A star that burns hydrogen in its core is called a main sequence star. The Sun is an example of a main sequence star. During these stages, the major forces that stabilize a star are the gravity and the thermal pressure. Thermal pressure due to the nuclear burning inside a star is the opposing force which stabilizes a star against the gravitational force. While a star acquires a helium core, as a result of core hydrogen burning, this core contracts and becomes hotter. Eventually, helium is ignited and burns. The product of helium burning is carbon and oxygen. While helium burns in the star's ...