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How Stars Are Born
For those of us lucky enough to see tiny little dots of light in the night sky, we all ask many questions about them. What are they? Where did they come from? How did they get there? Many of us are taught at young ages that all those stars are actually suns (with the exception of a few that are objects within our solar system, such as the other planets). Knowing how large and awesome our sun is, realizing that all those little dots are stars and some even bigger than the one we orbit around is fascinating! So what does it take for a star to form? Are they all the same? This hub provides answers based on our current knowledge.
What Is Needed
Stars form in turbulent conditions in what are called molecular clouds. These clouds are made up of gas and dust that is left over after a galaxy forms. They get their name because the clouds mostly consist of molecular hydrogen. Many stars form together in these clouds. As they form, they create winds and radiation that affects the stars forming around them. Some of the other stars will be torn apart while room is made for other new stars to take form.
During the embryonic, or beginning, stages stars are blanketed by one of two types of dust. One type is finger-shaped pillars of dust; the other is dark and thick threads (called filaments). Current research into star formation is attempting to understand how and why evidence suggests that the birth of new stars is triggered by larger stars in these filaments. As the stars complete their formation, they begin to drift away from each other as we are accustomed to finding them.
Types of Stars
Stars take on a couple of different forms which then determine their lifecycles and eventual death. Now that we have an idea of where and how they form, we can take a look at what they have formed into and the shape they will take as they continue their lifespans.
- T Tauri Stars: These are stars still in the process of formation.
- Main Sequence Stars: These are the most common types of stars. They take the shape of either red or yellow dwarfs. Their energy comes from nuclear fusion by converting hydrogen to helium. Red dwarfs are small, cool, faint, and the most common. Yellow dwarfs are small. The best example of a yellow dwarf is our sun.
- Giants: These are older stars that have reached a new phase. Red giants are approximately 100 times bigger than they were. They also become cooler. Blue giants are huge, very hot stars. They are now running on the helium they produced as main sequence stars.
- Supergiants: These are the largest known stars and can be as large as our solar system. Rare, these stars will eventually result in a supernova. Their deaths lead to the formation of black holes.
- Binary stars: A binary star is a set of two stars that are orbiting a shared center. They are believed to orbit closer and closer together until they collide or one dies and begins stripping matter from the other.
- Dying Stars: In the later stages of their lives, stars will form into a white dwarf, brown dwarf, neutron, or pulsar. A white dwarf is a former red giant, now the size of the earth. It is small, very dense, hot, and made mostly of carbon. It will lead to a black dwarf, which is a cold and black star. A brown dwarf is too small for nuclear fusion to take place. As a result, it is very faint. Neutron stars are small, incredibly dense, and composed of tightly packed neutrons with a thin atmosphere of hydrogen. Finally, a pulsar is a rapidly spinning neutron that emits a "pulse" of light.
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The stars we see today weren't always as serene as they appear, floating alone in the dark of night.
© 2012 Evylyn Rose