Astronomy 1021 Lecture : White Dwarfs

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Chris Racknor

Document Summary

White dwarfs are leftover cores of low intermediate mass stars. Their composition is helium for the lowest mass white dwarfs, primarily carbon for sun like stars and carbon/oxygen for intermediate mass stars. Resist gravity through degeneracy pressure, in this case electron degeneracy (electrons are as closely packed as allowed) High density because one teaspoon of wd material would weigh as much as a small truck. More massive wd s are actually smaller and denser then less massive ones. More mass -> stronger gravity -> contraction -> compress matter to higher density -> higher degeneracy pressure for equilibrium. Higher mass results in higher electron degeneracy pressure which in turn means higher speed of electrons. The maximum electron speed is the speed of light. The conclusion is that there is a limit to how massive a white dwarf can become and this limit is about.