ASTR 114 Lecture Notes - Lecture 10: Solar Constant, Chromosphere, Photosphere
23 Oct 2018
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Document Summary
Lecture 10 : as long as the sun shines. The sun is not only the largest object in our solar system - it is also the nearest example of a star. It produces energy by converting hydrogen to helium thereby maintaining a constant internal temperature. Gravitational potential energy / luminosity = 25 million years. Nuclear potential energy (core) / luminosity = 10 billion years. Interior structure of the sun : outer layers are not to scale, the core is where the nuclear fusion takes place. Luminosity: total energy radiated by the sun: it can be calculated from the fraction of that energy that reaches earth. Solar constant: amount of sun"s energy reaching earth- is approximately 1. 366 kilowatts per square meter. Total luminosity is about 4 * 10^26 w - the equivalent of 10 billion 1-megaton nuclear bombs per second. In equilibrium, inward gravitational force must be balanced by outward pressure.
