Explore the six most common types of stellar evolution stages. Learn about the main sequence, red giant, white dwarf, red supergiant, supernova, and neutron star/black hole stages.

6 Most Common Types of Stellar Evolution Stages

Stars are fascinating objects that have intrigued humans for centuries. These celestial bodies are not only responsible for providing light and warmth to our planet, but they are also the source of life as we know it. However, stars don’t remain the same throughout their existence. They go through a series of changes called stellar evolution. In this article, we will explore the six most common types of stellar evolution stages.

Main Sequence Stage

The main sequence stage is the longest and most stable phase in the life of a star. It is during this stage that the star is actively burning hydrogen into helium in its core. This process releases energy, which counteracts the gravitational forces pulling the star inward. The main sequence stage lasts for billions of years, depending on the star’s size and mass.

Stars on the main sequence stage come in different sizes and colors. Small stars, also known as red dwarfs, can burn hydrogen for trillions of years. Medium-sized stars, like our sun, will burn hydrogen for about 10 billion years. Large stars, on the other hand, can burn hydrogen for only a few million years.

Red Giant Stage

As a star runs out of hydrogen fuel, it begins to evolve into a red giant. During this phase, the star’s core contracts while the outer layers expand and cool down, giving the star its characteristic red color. Red giants can be up to 100 times larger than their original size, and they are much cooler than main sequence stars.

Red giants are known for their instability and variability. They can pulsate and change in brightness over short periods of time. Red giants eventually exhaust their fuel and shed their outer layers, leaving behind a hot, dense core known as a white dwarf.

White Dwarf Stage

White dwarfs are the remnants of low to medium mass stars, such as our sun. These stars have exhausted all their fuel and have shed their outer layers, leaving behind a hot, dense core made mostly of carbon and oxygen. White dwarfs are incredibly dense, with a mass comparable to our sun packed into a sphere about the size of the earth.

White dwarfs don’t generate their own energy but rather cool down over time. They will eventually become black dwarfs, which are essentially cold, dead stars that emit no light or heat.

These are the first three stages of stellar evolution. The next three stages involve high-mass stars and are much more dramatic. We will explore these stages in the second part of this article.