The Final Stage in the Life Cycle of a Star like the Sun is a White Dwarf

The life cycle of a star like the Sun can be divided into several stages: formation, main sequence, red giant, and white dwarf. The final stage in this life cycle is a white dwarf.

Formation of a Star
Stars like the Sun are formed from massive clouds of gas and dust called nebulae. The force of gravity causes the nebula to collapse, and as it collapses, it forms a dense core called a protostar.

Main Sequence Stage
Once the protostar reaches a certain temperature and density, nuclear fusion begins, and the star enters the main sequence stage. During this stage, the star steadily fuses hydrogen into helium in its core, releasing a tremendous amount of energy. This energy counteracts the gravitational force, maintaining the star's stability.

Red Giant Stage
After spending billions of years in the main sequence stage, a star like the Sun eventually exhausts its hydrogen fuel. As a result, the core contracts and heats up, causing the outer layers of the star to expand and cool. The star then enters the red giant stage. In this stage, the star becomes much larger and brighter, as it starts fusing helium into heavier elements like carbon and oxygen.

White Dwarf Stage
Once the red giant stage ends, the outer layers of the star are expelled into space, forming a beautiful cloud of gas and dust called a planetary nebula. What remains is a hot, dense core known as a white dwarf.

A white dwarf is about the size of the Earth but incredibly dense, with the mass of a star compressed into a small volume. It is composed mainly of carbon and oxygen, and its high temperature is sustained by residual heat from the red giant stage. Without nuclear fusion, the white dwarf gradually cools over billions of years, eventually becoming a cold, dark object known as a black dwarf. However, no black dwarfs have been observed yet, as the universe is not old enough for any white dwarfs to have completed this transition.

In conclusion, the final stage in the life cycle of a star like the Sun is a white dwarf. It is formed after the star goes through the main sequence and red giant stages, and it represents the remnant core of the star after it has shed its outer layers.