Hydrostatic Equilibriu1

Hydrostatic Equilibriu1 - Hydrostatic Equilibrium Controls...

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Hydrostatic Equilibrium Controls the Reaction Rates Hydrostatic equilibrium is the balance between the thermal pressures from the heat source pushing outwards and gravity trying to make the star collapse to the very center. I will discuss hydrostatic equilibrium in more depth (no pun intended) in a later section. The nuclear fusion rate is very sensitive to temperature. It increases as roughly temperature 4 for the proton-proton chain and even more sharply (temperature 15 ) for the Carbon-Nitrogen-Oxygen chain. So a slight increase in the temperature causes the fusion rate to increase by a large amount and a slight decrease in the temperature causes a large decrease in the fusion rate. Now suppose the nuclear fusion rate speeds up for some reason. Then the following sequence of events would happen: 1) the thermal pressure would increase causing the star to expand; 2) the star would expand to a new point where gravity would balance the thermal pressure; 3) but the expansion would lower the temperature in the core---the nuclear fusion rate would slow down; 4)
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Hydrostatic Equilibriu1 - Hydrostatic Equilibrium Controls...

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