The Sun - atmosphere very low density(about 1/1000 of an...

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The Sun Introduction and General Properties   Sun is a typical star stars are balls of hot gas Basic numbers: mass = 330,000 x Earth volume = 1 million x Earth surface gravity = 28 x Earth luminosity = 4 x 10 26  watts surface temperature = 5780 K core temperature = 15 million K composition: o 73% Hydrogen o 25 % Helium o 2 % other differential rotation o 25 days at equator o 30 days near poles Structure of the Sun
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  1. Core: source of energy: nuclear fusion atomic nuclei combine converts mass to energy (E = mc 2 ) requires very high temperatures and pressures 2. Radiative Zone energy from core transferred out by absorption and re- radiation of light temperature drops gradually 3. Convective Zone energy transferred out by convection boiling motion in the gas 4. Photosphere Sun's "surface" very thin layer (300 - 400 km thick (like Earth's 
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Unformatted text preview: atmosphere) very low density (about 1/1000 of an atmosphere) gas is cooler here => absorbs light => source of absorption line spectra from Sun surface is divided into cells = "granulation" Granules are 500 - 1500 km across (Texas is about 1500 km across) lifetime of a cell is about 10 minutes 5. Chromosphere cloud of hot rarefied hydrogen heat => emission line spectra from here observe larger granulation and jets of gas (spicules) penetrating layer 6. Corona irregularly shaped cloud of rarefied ions very hot (not clear why it is so hot) shape changes 7. Solar wind flow of charges particles away from the Sun • comes out of coronal holes • low density • fast (about 400 km/sec at Earth) • extends out beyond Neptune • governed by magnetic fields...
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The Sun - atmosphere very low density(about 1/1000 of an...

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