White Dwarfs - White Dwarfs White dwarfs form as the outer...

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White Dwarfs White dwarfs form as the outer layers of a low-mass red giant star puff out to make a planetary nebula. Since the lower mass stars make the white dwarfs, this type of remnant is the most common endpoint for stellar evolution. If the remaining mass of the core is less than 1.4 solar masses, the pressure from the degenerate electrons (called electron degeneracy pressure ) is enough to prevent further collapse. Because the core has about the mass of the Sun compressed to something the size of the Earth, the density is tremendous: around 10 6 times denser than water (one sugarcube volume's worth of white dwarf gas has a mass > 1 car)! A higher mass core is compressed to a smaller radius so the densities are even higher. Despite the huge densities and the ``stiff'' electrons, the neutrons and protons have room to move around freely---they are not degenerate. White dwarfs shine simply from the release of the heat left over from when the star was still producing energy from nuclear reactions. There are no more nuclear reactions occurring so the
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White Dwarfs - White Dwarfs White dwarfs form as the outer...

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