Astronomy 1011A/B Lecture Notes - Lecture 14: Electron Degeneracy Pressure, Degenerate Matter, White Dwarf

• School: Western University
• Department: Astronomy
• Course: Astronomy 1011A/B
• Professor: Prof.a

Document Summary

Electron degeneracy pressure means that two electrons can"t occupy the same state in the same place. Degeneracy pressure is important to neutron stars and white dwarfs because it is what allows them to resist the pull of gravity. White dwarfs have high temperatures and low luminosities cool off and grow dimmer with time. Because nothing can move faster than light, a white dwarf cannot be more massive than 1. 4msun, the white dwarf limit (also known as the chandrasekhar limit). A star that started with less mass gains mass from its companion. Eventually, the mass-losing star will become a white dwarf. Mass falling toward a white dwarf from its close binary companion has some angular momentum. The matter therefore orbits the white dwarf in an accretion disk. Accretion disks: friction between orbiting rings of matter in the disk transfers angular momentum outward and causes the disk to heat up and glow. Nova explosion drives accreted matter out into space.