Final answer:
The Sun's life cycle comprises of the Main Sequence, Red Giant, Helium Burning, and White Dwarf stages. Its lifespan depends on initial mass, and its size, temperature, and luminosity, as well as the core's composition, change throughout these stages. Stars with more mass burn out faster due to increased fusion from gravitational pressure.
Step-by-step explanation:
The life cycle of the Sun can be separated into several key stages: Main Sequence, Red Giant, Helium Burning, and finally, White Dwarf. Throughout these stages, the Sun's size, temperature, and luminosity will change. Initially in the Main Sequence stage, which lasts around 10 billion years, it's hot and dense enough for hydrogen in its core to fuse into helium, generating energy and heat. When hydrogen in the core is mostly used up, the Sun evolves into the Red Giant phase, increasing dramatically in size. The helium core then starts to collapse under its own gravity, and the external layers expand.
The core gets hot enough to start the Helium Burning phase, where helium is fused into carbon and oxygen. During this stage, the Sun’s size decreases, but its temperature and luminosity increase. Lastly, as the helium runs out, the Sun becomes a White Dwarf.
The life span of the Sun is dependent on its initial mass. Compared to other stars, more massive stars burn out faster due to their greater gravitational pressure causing more intense fusion. The composition of the Sun's core changes from primarily hydrogen to helium in the Main Sequence stage, then to carbon and oxygen in the Helium Burning stage.
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