White Dwarf
From Slackerpedia Galactica
White Dwarf is a monthly magazine published by Games Workshop in the UK, targeted at role playing and tabletop gamers. The magazine was created in the 1970's by Steve Jackson and Ian Livingstone
A white dwarf is also the product of the death of a low or medium mass star. It puffed out its outer layers of Hydrogen and Helium forming a planetary nebula around the left over core, made up mostly of Carbon with some Oxygen. Over the course of trillions of years, this core will cool down and fade. The Universe isn't old enough yet for any white dwarf to have totally cooled yet. The Sun will become a white dwarf in about 4-5 billion years.
White dwarfs are very dense. They are made up mostly of degenerate electrons, which are electrons pressed so closely together that they can't possibly get any closer without violating the Pauli Exclusion Principle (which sometimes happens and creates a neutron star).
In binary stars, white dwarfs often pull material from a younger companion. This material usually forms an accretion disk around the white dwarf (unless the white dwarf has an intense magnetic field). Sometimes the accretion disk gets so full that it erupts in an outburst. These are called dwarf novae or novae. Occasionally, the mass of the disk gets really big, then it erupts as a Type-Ia supernova. This completely blows apart the white dwarf, leaving nothing behind.
External Links
Introduction to White Dwarfs via Imagine the Universe
Slacker Astronomy audio podcast about Sakurai's Object and what happens right before a White Dwarf is formed
