7th Week: Stellar Structure and Evolution B: Difference between revisions
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==Hydrostatic hydrogen burning== | ==Hydrostatic hydrogen burning== | ||
Hydrogen burning produces more energy than any other fuel consumed in stars. | Hydrogen burning produces more energy than any other fuel consumed in stars. This form of burning is also highly favored for young stars as they consist mostly of hydrogen. Also, this burning stage marks the star as a main sequence star. | ||
===pp chain=== | ===pp chain=== | ||
The pp chain is the process by which protons undergo fusion to helium. This chain actually comes in three forms but is dominated mostly by the ppI chain. This process occurs in three steps. The first is the fusion of two protons to form deuterium. Naturally one would assume that the two protons would form helium-2 but this is not within the drip-line. | |||
===CNO cycle=== | ===CNO cycle=== | ||
Revision as of 22:07, 19 March 2009
Stellar properties
Hertzsprung-Russell Diagram
Its a diagram generated by plotting the luminosity of the stars against their temperature at the surface. Here luminosity is the amount of energy a body radiates per unit time. This quantity is often measured in solar luminosities. One solar luminosity is equal to W.
Stellar evolution
All stable stars maintain a balance between the force of gravity and the internal pressure, preventing them from collapsing. In stellar plasma there are several reaction networks. The reactions with the smallest Coulomb barrier take place in the shortest time and are responsible for most of the nuclear energy generation.
Hydrostatic hydrogen burning
Hydrogen burning produces more energy than any other fuel consumed in stars. This form of burning is also highly favored for young stars as they consist mostly of hydrogen. Also, this burning stage marks the star as a main sequence star.
pp chain
The pp chain is the process by which protons undergo fusion to helium. This chain actually comes in three forms but is dominated mostly by the ppI chain. This process occurs in three steps. The first is the fusion of two protons to form deuterium. Naturally one would assume that the two protons would form helium-2 but this is not within the drip-line.