PHYS 1121 Lecture Notes - Interstellar Cloud, Red Supergiant Star, Hydrostatic Equilibrium
Document Summary
Formed from the collapse of interstellar cloud consisted of hydrogen & helium. If the mass is not big enough (not enough atoms) it will remain hydrostatic equilibrium. Hydrostatic equilibrium:- gravitational force pushing inward and the heat(kinetic energy) pushing outward. Few atoms --> heat prevails over gravity and cloud will disperse. # of atoms increases, cloud undergoes a gravitational collapse. As matter collapse, heat increases, and triggers hydrogen fusion (proton-proton chain reaction) = star. When all the hydrogen from the core is burned, the collapse continues. Hydrogen of the outer shell starts to fuse(shell burning) He consumed rapidly and luminosity increases until the fusion ends. Core shrinks but outer shells are ejected = planetary nebulae. All that is left is a small carbon core(still hot) but begins to cool down. Then becomes a white dwarf and then a black dwarf (no longer emits light) Supernova:- when the star collapses and produces an extremely large release of energy.