Why stars have spectra

Questions for thought

1. When were solar spectra discovered?
2. When was the modern conception of the atom (Bohr atom) introduced? This allowed emission and absorption spectra to be explained in relationship to specific phenonmena with an atom.
3. If you look at the corona of the Sun during an eclipse. What is it about the geometry of the situation that makes the light have to have originated in the corona rather than directly emitted by the Sun? Drawing a diagram might help.
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Notes

1. The logic of what generates continuos spectra, what absorbs and emits light is confusing when applied to the Sun. The temperature of the surface of the Sun is much lower than in the corona.

Related resources

• Spectroscopy: Unlocking the Secret in Starlight
  Explains how spectra are produced by stars and how this information is used to study stars. Excellent resource for AP physics students and science teachers.
  Australia Telescope Outreach and Education
  
• Spectral Classification of Stars
  University of Nebraska
  
• High Resolution Solar Spectrum
  Detailed view of our Sun's spectrum in the visual range.
  National Optical Astronomy Observatory
  
• High resolution spectrum of Arcturus
  Detailed view of the star Arcturus in the visual range.
  National Optical Astronomy Observatory
  
• Solar and Heliospheric Observatory
  "a project of international collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind." Breathtaking images and movies of our Sun.
  Solar and Heliospheric Observatory
  
• Emission and absorption lines of different elements
  Department of Physics, University of Oregon
  
• What do spectra tell us?
  Goddard Space Flight Center, NASA