Cycle of a Star

Emma Sauerwein

Interstellar Medium

The Interstellar Medium is the space between stars (space). Interstellar gas is made up of 75% hydrogen and 25% helium.

Stellar Nebula

This is a cloud of Hydrogen gas and dust. They are the birthplaces of stars.

Equilibirum is established

Equilibrium means that there is not an overall change in the star. The gas pressure which is from nuclear fusion. pushing out from the center is equal with the gravity pulling atoms inward to the center.

Birth of a Star

After Equilibrium is established Nuclear Fusion (The process of converting atoms into different atoms.) Is established which starts because of the release of a lot of energy. This is represented as the equation E=mc2 starting with hydrogen and helium.

Second Phase

This is the main sequence, the main sequence is when stars are fusing hydrogen into helium, and helium and hydrogen into carbon. Most stars go into this phase unless they cannot establish equilibrium. At the end of this phase the star runs out of hydrogen and fuses helium into heavier elements. Luminosity becomes much greater can be 1million times greater than the sun. Temperature becomes much lower at about 2000-3000 Celsius. Volume becomes much greater than the sun due to increase in size.

Third Phase

The next phase in a star's life is called the Red Giant. This is when the star runs out of hydrogen fuel and has more of helium, nitrogen, and carbon in it's core. It becomes a large bright star with a cool surface. The star stays in this phase depending on how big the star is.

The Last Phase

This phase is the White Dwarf or Death phase, the last phase of a star. The White Dwarf is the shrunken remains of a star which is what a Red Giant turns into. A star can also die by turning into a supernova, which is an explosive death of a star they can also turn into a neutron star which takes place after a supernova when the protons and electrons combine making a neutron star. The final way is for a star to turn into a black hole, which is a gravitational pull of a star forcing all light, time, and depth to become distorted. Stars deaths are different depending on the size of the star.

Star's light

A star's composition can be determined by using a certain type of telescope like the Hubble telescope. The certain light determines what is in it using the Emission Spectrum which can help determine about what stage it is at. Also, this can help see if a star is moving using the Doppler affect to see if it is red shifted (moving away from us) or blue shifted (moving towards us).
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Origin of Elements

All elements come from stars, except for two, Hydrogen and Helium, these to elements originated from the big bang theory. These two elements in then in stars started to fuse which then created new elements like carbon and oxygen, then they created other elements like nitrogen and magnesium, and finally towards the end of a stars life cycle it creates at the center of its core the elements fuse to create Iron.
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Works Cited

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