CAS AS 102 Chapter Notes - Chapter 17: Triple-Alpha Process, Helium Flash, Degenerate Matter
Document Summary
As the core contracts, h begins fusing to he in a shell (gas_ around the core - h shell fusion. Luminosity increases because core thermostat is broken. Increasing fusion rate in shell does not stop core from contracting. New he in shell keeps adding mass to he core and assists gravity. H-fusing shell shrinks along with core, growing hotter and denser. Fusion rate continues to rise, feeding even more he to core. Star caught in in vicious circle with broken thermostat. Core and shell continue to contract and heat while sun as a whole continue to grow larger and more luminous. Finally temperature of he core reaches 100 million k and helium fusion begins. Sun"s increasing radius continues to weaken gravity at its surface. Large amounts of mass escapes via solar winds. Helium fusion does not begin right away because it requires higher temperatures than hydrogen fusion - larger charge leads to greater repulsion.
