AST 101 Lecture Notes - Lecture 14: Supernova Remnant, Degenerate Matter, Low Mass
Document Summary
High mass star life track after main sequence. Core temp in stars with >8m(sun) allow fission of elements as heavy as iron. Advanced reactions in stars make elements such as si, s, ca, fe. Advanced nuclear burning proceeds in series of nested shells. Inner most shells happen later in the star"s life. Evolves through advanced stages of fusion luminosity remains roughly constant, but its size increases. Once carbon ignites, the end is near. Massive stars in late stages of evolution move very quickly so we shouldn"t see too many stars in the top part of the hr diagram. Nuclear reactions involving iron don"t release energy. Iron has lowest mass per nuclear energy = least amount of energy. Iron builds up in core until degeneracy pressure can no longer resist gravity. Luminosity increases with time as shell burning and contracting releases more. Star starts to get physically larger in response to additional energy.
