ASTR 121 Lecture Notes - Lecture 7: Cosmic Distance Ladder, Type Ia Supernova, Light Curve
Document Summary
Cooling balls of helium or carbon or oxygen. Accretion beyond 1. 4 solar masses will cause white dwarf supernova. Cannot be more than 1. 4 solar masses because of the speeds of electrons. They don"t wanna be near each other but create pressure when pushed together. White dwarves are remaining cores of dead stars. Electron degeneracy pressure supports these against the crush of gravity. White dwarves are small with the same mass as the sun and are about the size of the sun. A single teaspoon of white dwarf matter would weigh several tons on earth. Degeneracy can"t support stars of arbitrarily large masses. For white dwarf, the limit is 1. 4 solar masses. Mass falling towards a white dwarf from a close companion has angular momentum. The matter will therefore orbit the white dwarf in accretion disk. Friction in the disk causes the matter to. The temperature of accreted matter eventually becomes hot enough for hydrogen fusion.