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By | November 2012
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Devyn Parsons
Astro-10
5/6/12
Oral Presentation Paper
White Dwarfs
A White Dwarf is a small star composed mostly of electron-degenerate matter. A white Dwarf is also described as the last stage in the life cycle of a massive star like our sun. White Dwarfs have a strong density which astronomers compare to the sun. White Dwarfs’ mass is also comparable to the sun and its volume is comparable to the Earth. A white dwarf can get very hot and exceed up to 100,000 kelvins. White Dwarfs are stars that have burned up all of the hydrogen they once used as nuclear fuel. White Dwarfs can also be referred to as a Degenerate Dwarf. The upper limit to the mass of a white dwarf star is about 1.4 times the mass of the sun, also known as Chandrasehkar’s limit. When White Dwarfs lose their heat and light they then are called “Black Dwarfs”. When White Dwarfs become Black Dwarfs they then become invisible. The first white dwarf ever observed is called “Siruis B” and was discovered by Alvan Clark in 1862. White Dwarfs eventually got its name “White Dwarf” in 1922 by Willem Luyten. In 2009 researchers counted 8 white dwarfs among the hundreds of star systems nearest to the sun. Surprisingly there is a dramatic difference between a regular neutron star and a White Dwarf. Unlike most other stars that are supported against their own gravitation by normal gas pressure, white dwarf stars are supported by the degeneracy pressure of the electron gas in their interior. Degeneracy pressure is the increased resistance exerted by electrons composing the gas, as a result of stellar contraction. The central core of a typical white dwarf is composed of a mixture of carbon and oxygen. White dwarf stars are occasionally found in binary systems. A teaspoon of material in a white dwarf is about as heavy as a spoonful of syrup. Our sun will be considered a White Dwarf in about 6 billion years. (Predicted) On average the same size as Earth. 99% of all stars will eventually...

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