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I Distinguishing Blackbody and Atomic Spectra of the Sun

  1. Apr 29, 2016 #1
    Scientists have measured both the blackbody spectrum and also the atomic spectra of various elements in the Sun.

    How do they distinguish between the two and filter out the light from either one?
  2. jcsd
  3. Apr 29, 2016 #2
    The blackbody spectrum and what you call the atomic spectra of the sun is one and the same. There is only one spectrum called the absorption spectrum. Scientists use that and look at the absorption lines to find out what elements are in the sun.
  4. Apr 29, 2016 #3
    Oh, right. They can only use the absorption spectrum.
  5. Apr 29, 2016 #4
    Yes. When they collect light from the sun they only get one spectrum to use ready made. No filtering required.
  6. Apr 29, 2016 #5

    Charles Link

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    The surface temperature of the sun is approximately 6000 K. The spectrum would be a blackbody except that cooler gaseous elements just outside the sun will sometimes be found in the ground state and lower excited states. These are able to then absorb energy from the blackbody at wavelengths corresponding to atomic transitions more so than the energy that they re-radiate. The result is a spectrum of approximately a T= 6000 K blackbody except for narrow atomic absorption lines where the energy is somewhat less than the blackbody curve intensity. For an earth-based system, you need to ensure that the observed absorption lines (deviation from a smooth blackbody curve )didn't occur from elements and molecules in the earth's atmosphere.
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