AST 307 · Introductory Astronomy
Fall 2003


Chapter 18  Oct. 22

  1. Describe how interstellar dust can be observed through its effects on starlight that passes through it.

  2. How can an astronomer distinguish between a star that has been reddened by dust and one that is red because it is cool, or one that has had its spectrum Doppler shifted?

  3. Describe interstellar dust grains. Typically how big are they, and what are they made of?

  4. Describe the spectrum of light coming from emission nebulae.

  5. How does ultraviolet radiation from hot stars cause the gas in emission nebulae to glow?

  6. Describe how astronomers can observe interstellar atomic gas. Include a description of absorption lines seen at visible and ultraviolet wavelengths and microwave '21 cm' emission.

  7. How do molecules in molecular clouds emit radio wavelength emission lines?

29 October 2003
Astronomy Program · The University of Texas at Austin · Austin, Texas 78712
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