11.19.2007 - Astronomy notes

11.19.2007- - 11.19.2007 Astronomy Solar Mass Stellar Evolution Main sequence star Hydrostatic equilibrium pressure and gravity are balanced After

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11.19.2007 – Astronomy Solar Mass Stellar Evolution Main sequence star Hydrostatic equilibrium pressure and gravity are balanced - After establishing main sequence, helium core grows - Core temp = 1.5 E 7 K (too cold to burn helium) - Process continues for about 10 billion years Hydrogen shell burning – not a stable configuration off of main sequence to 8. Subgiant Branch - helium core contracts - core pressure increases, temperature increases - core temp = 5 E 7 K (still too cold to burn helium) - but heats up the hydrogen shell burn rate increases - luminosity increases - outer star expands and cools 9. Red Giant Branch - one mercury orbit across - core is only a few earths across - (star looks really big, but most of the mass in concentrated in the core) - helium core continues to contract - core pressure increases to the maximum allowed by quantum mechanics - electron degeneracy pressure material acts like a liquid - gases are compressible and expandable; liquids and solids are not
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This note was uploaded on 09/24/2009 for the course ASTR 101 taught by Professor Christiansen during the Fall '08 term at UNC.

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11.19.2007- - 11.19.2007 Astronomy Solar Mass Stellar Evolution Main sequence star Hydrostatic equilibrium pressure and gravity are balanced After

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