NATS 1870 Lecture Notes - Lecture 21: Crab Nebula, Rayleigh Scattering, Solar Mass
20 Jun 2016
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Document Summary
The death of extremely massive stars; anywhere from 15 x msun -> 80 x msun is a supernova exploding star. The explosion generates tremendous amounts of energy -> the energy gets deposited into the material around the star. 1054 ad supernova occurred; today we see its remnant as the crab nebula . Energy source: energy from shock wave -> puts electrons in a surrounding material into higher orbits. When the electrons go back down to a lower orbit, photons are emitted. Dark nebulae: dense, cool areas of the interstellar medium. Reflection nebulae: blue colour comes from rayleigh scattering. Dust particles scatter short wavelengths when they have the correct size. Astronomers take images of astronomical objects through filters that isolate particular wavelength windows. Example of the narrow band: h-alpha at 656 nm (red) isolates the jump from 3 rd 2nd energy level of hydrogen. When astronomers use wavelengths outside of visible spectrum: a map is created to show the data.
