PHYS 183 Chapter Notes - Chapter Lectures 12 and 13: Solar Radius, Earth Radius, Solar Core
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11. 1, 11. 2, 11. 3, 11. 4 (lectures 12 and 13): Stars are different from planets in that they make their own light. So they must have a very powerful source of energy. Mass (msun): 2 x 1030; radius (rsun): 700,000 km; rotation period: about 29 days; Age: about 5 billion years old; power/luminosity (lsun): 2 x 1033 erg/s or 2 x 1026. 1,300,000. (v=4/3 r3 earth"s volume: 1. 083 x 1012 sun"s volume: 1. 412 x 1018) The solar core is where nuclear reactions (fusion) occur. The photosphere is the visible surface of the sun. Energy for the center is sent out via convection. Nuclear reactions generally involve only the nucleus. Mass cannot be created or destroyed it is conserved . A fission reaction occurs when an unstable parent nucleus (m) is split into two more stable daughter nuclei (m and m). E=mc2 (energy = mass x the speed of light squared)
