NATS 1740 Chapter Notes - Chapter 17: Triple-Alpha Process, Helium Flash, Fusion Power

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Tatiana Paulin

Document Summary

Main sequence stars with large masses have much greater luminosities than those with small masses, so their cores release fusion energy at great rates. Stars born with less that 2 solar masses. Have deeper convection zones because it is hard for photons to carry light at low temperatures. As the # of particles drops in the core from fusion, the core shrinks and heats up to keep pressure in balance with gravity. This rise in temp increases the rate of fusion slowly and therefore increases the luminosity as well as the star ages. When hydrogen runs out and fusion stops, gravity will pull inward and the stars core will begin to shrink. The outer layers expand outwards even though the core is shrinking. The star will become a subgiant( a star between a main sequence and giant) with a helium core and hydrogen fusing shells. As the outer layers expand, the luminosity will increase.