A star is a large, bright ball of gas that are constantly exploding, burning, and using fuel. They can be made of a few different kinds of elements, but they are usually composed of hydrogen and helium. The star retains its shape and form because gravity is constantly pulling the gasses and materials inwards toward the star’s center.
How do Stars Create Light?
Stars are different than planets because stars emit light. Stars emit light through a process known as nuclear fusion, which happens at their cores. During this process, two hydrogen atoms in the core float around and slam into each other. When the hydrogen atoms meet, the fuse together to create a helium atom. During the fusion process, some of the hydrogen is converted into energy.
The energy released by nuclear fusion in stars makes up what we know of as heat, Ultraviolet rays, and visible light. It is also what makes the stars twinkle and glow.
How are Stars Made?
Stars are made in large fields that are made up of clouds of gas and dust. These clouds begin to collapse and pull towards one single point. The material that collapses and is compressed at the center becomes the material that makes up the star.
Sometimes not all the gas and dust collapse to make up the star. The gas and dust that do not make it into the star body simply swirl, float, and rotate around the newly formed star.
This process is known as “Star Formation Theory.”
How Do Stars Die?
Stars begin to die when they run out of fuel and can no longer continue nuclear fusion. Once stars begin to use up all of their fuel, they enter their final stages of life. The stage they enter depends on their mass.
Stars that are less than the size of our Sun begin using and fusing the helium in their core instead of the hydrogen. \As these stars use the helium, the energy they emit increases. The increase in energy causes their outer layers to bulge out, making the star larger.
As the layers are pushed outward, they begin to cool down and turn red in color. These dying stars are called red giants. Slowly, the red giant will continue to burn out and become a white dwarf.
Bigger stars experience different final stages of life. The gravity of the bigger stars is significantly larger, creating more compression and pressure in the core. The star begins to use its energy by fusing heavy elements and shining brightly. These stars include the ones just born as well as the ones reaching the final stages of their life.
Once the big star has used up all of its fuel, the core will implode. The implosion creates a violent supernova explosion. After the explosion, all that is left behind is either a black hole or a neutron star.
What are the Different Types of Stars?
Stars can come in many different colors and compositions. Stars are mostly categorized by their color, which helps indicate their temperature. Stars can also be placed into descriptive categories based on their place in the star lifecycle. Generally, a star can be considered protostars, main sequence stars, giants, supergiants, white dwarfs, and neutron stars.
- Protostar – A protostar is a star that is still forming. This is the stage of the star when gasses are collapsing inward to build a star. A protostar exists for up to 100,000 years until it begins to take a star shape. Then, the protostar can evolve into a T Tauri Star, which is the moment before it becomes a full-blown main sequence star.
- Main sequence stars – Main sequence stars make up most of our galaxy. They have different sizes, shapes, temperatures, and colors. However, all main sequence stars release light and energy through nuclear fusion.
- Red Gaints – Red Giants are stars that are beginning to die. Red Giants are stars that have pushed their layers outward as a result of burning the last of their fuel. Giants can become nearly 100 times larger than their original size. Red giants usually turn into white dwarf stars.
- Supergiants – Supergiants are massive stars that form, live, and die quickly. They tend to be unstable because of their giant sizes, so they burn hydrogen quickly. When they die, they tend to explode and fall to pieces.
- White Dwarf – A white dwarf is a star that has run out of fuel, and it no longer has enough gravity or pressure to continue nuclear fusion. Essentially, a white dwarf is a dead star. White dwarfs shine white light because they are still hot, but they begin to cool down slowly.
- Red Dwarf – Red dwarf stars, on the other hand, are stars that are small and have smaller masses. Since dwarf stars are small, they have lower temperatures and are better at maintaining nuclear fusion for longer periods of time, meaning they live longer.
- Neutron Stars – Massive stars that die become neutron stars, which are the cores of stars left behind after an explosion. These stars have extremely strong gravities. Some large stars may not become neutron stars and become black holes instead.
What are Some Famous or Well-Known Stars?
- The Sun – The most well-known star is our Sun, which burns at the center of our Solar System and provides energy for human life.
- Sirius – Sirius is perhaps the second most well-known star. This is the brightest star in the night sky. Known as ‘The Dog Star,’ Sirius is about 8.6 light-years away.
- Polaris – Polaris is famously known as the North Star. This star helps give direction to travelers and explorers because it essentially stays in the same place in the sky towards the northern pole. You can find Polaris by looking for the handle of the Little Dipper or find the Big Dipper pointing to it.
Interesting Facts About Stars
- Scientists study the energy of stars by using Ultraviolet light and X-rays.
- The stars that live in the halo of the Milky Way Galaxy are some of the oldest stars in our Galaxy.
- Stars can exist in a binary star system, meaning that two stars orbit the center of their system.
- Some white dwarfs have been shown to orbit each other until they merge, which has the potential to cause explosions.
- Scientists use spectroscopy to help study the chemistry and composition of stars and the clouds around them. They study the atoms and molecules of each star.
- The hottest stars are white and blue while the colder stars are orange and red.
- Stars can change color during their lifetime.
- Alpha Centauri C is the star system closest to our Solar System.
- Read: What is a Mean Sun and mean Solar Day?
- Read: Does the sun rotate?
- Read: Are we getting closer to the sun?
- Read: What are Circumpolar Stars?
- Read: Why do stars appear to twinkle?