AST 307 · Introductory Astronomy
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Fall 2003
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Topics
Chapter 23 Nov. 12-14
- Describe the method astronomers use to determine the distances
to RR Lyrae and Cepheid variable stars from their fluxes and
pulsation periods.
- Describe how RR Lyrae stars were used to show that the Sun is
not at the center of the Milky Way Galaxy.
- Draw a sketch of the Milky Way Galaxy showing the disk, halo,
bulge, spiral arms, and globular clusters.
- Describe the patterns of motion that are seen for the stars in
the disk and in the halo of the Milky Way. In particular,
describe how orbital speeds of stars depend on distance from the
center.
- Explain why the density wave theory is needed to explain the
persistence of the spiral arms, and how it accomplishes this.
- Describe the evidence for dark matter in the outskirts of the
Milky Way.
- Describe the evidence for a massive black hole at the center of
the Milky Way.
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