AST210H1 Chapter Notes - Chapter 17: Galactic Center, Solar Mass, Density Wave Theory
16 Apr 2017
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Document Summary
Herschel and kapteyn tried to measure the size of the galaxy and the location of the sun within it o. Both were wrong because of interstellar dust obscuring visible light (extinction: couldn"t see far, like counting trees in a forrest. Thought (based on the faulty data) that the sun was in the center. Oort and lindbland measured motion of stars around the sun, supported shapley"s findings of stars orbiting the galactic center. The disk o o large flat plane star formation: most crowded part, o and b stars = new population i stars, metal rich (so born from old dead stars) bluer. Nuclear bulge: most dense area, no star formation (redder) Halo o globular clusters here: old stars that orbit the center through the disk (outside of the plane, population ii stars, metal poor (first gen stars) 21-cm radiation is composed of low energy photons in the radio spectrum.
