3. Convection and Solar Radiation
- Page ID
- 5948
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Source: <http://buffonescience7.wikispaces.com/3)++Our+Star+(Sun)+-+Ch+4.2>
The sun's core temperature is around 20,000,000 °K, yet it is not what determines the characteristic electromagnetic radiation emission from the sun, because most of this intense core radiation is absorbed by a layer of negative hydrogen ions outside the sun’s core called the convection layer. Heat from the core interior passes through the radiative zone, and then accumulates in this convection zone. Once here, currents circulate so that heat is passed to the photosphere at the surface of the sun and the cooler plasma flows back down to carry more energy to the photosphere. The convection process allows heat to be released from surface with gas, much like boiling water releases heat from the water’s surface in steam.
In the particle view, photons are essentially bouncing around in the region between the core and the photosphere, losing energy and traveling through the convection zone to the photosphere. These photons are then radiated with gases which are still a very high 5760 °K. Because the sun essentially radiates like a blackbody, its spectral distribution is determined by a specific temperature; it turns out its spectral distribution is determined by the temperature of the photosphere, or the surface of the sun. Thus its spectral distribution is comparable to that of a blackbody at around 6000 °K (see Solar Radiation Outside the Earth’s Atmosphere).