AST101H1 Lecture Notes - Rogue Planet, Thermostat, Doppler Spectroscopy
15 Mar 2014
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AST101H1 Full Course Notes
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The solar thermostat stabilizes energy production in the core. Nuclear fusion occurs in the sun"s core --> uses hydrogen to create helium. The physical conditions inside the sun work like a natural thermostat. A slight drop in core temperature makes the particles in the core slow down. This leads to a large decrease in fusion, because for fusion to occur the particles must be moving very fast. This in turn lowers the core pressure, causing the core to contract and heat up, and restore the fusion rate to normal. This process also works in reverse, if the sun"s core gets a little hotter. Know how to do this on the exam. We have discovered hundreds of extrasolar planets, and have candidate planets for thousands. Extrasolar planets, or exoplanets, are planets orbiting a star other than the sun. Rogue planet: a planet which isn"t orbiting a star. Exoplanets are very hard to image directly. We deduce the presence of exoplanets indirectly.
