Identify the general types of spectra produced by stars, emission nebulae, galaxies and quasars

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Identify the general types of spectra produced by stars, emission nebulae, galaxies and quasars

  • Due to cool atmosphere of stars, they produce absorption spectra.
  • Emission nebulae are regions of hot gas that produce emission spectra.
  • Emission nebulae also show a faint continuous spectrum produced by the reflection of starlight.
  • Galaxies produce an almost complete spectrum.
  • Most galaxies emit light characteristic of older stars.
  • Some galaxies show emission lines due to absorption of ultraviolet light by gas clouds surrounding new stars.
  • As most galaxies are receding from our point of view, their spectra are generally strongly red-shifted.
  • Quasars are point sources like stars that emit more radiation than most galaxies and exhibit very large red shifts.
  • Spectrum from quasars consists of continuous spectrum plus a few emission lines that fluctuate rapidly in intensity.