Exam 12: The Milky Way Galaxy

Radio maps of our galaxy show spiral arms because

What is the difference between an open cluster, an association, and a globular cluster? In which components of the galaxy does each lie?

In the diagram below, the approximate absolute magnitude of a Type II Cepheid with a period of 30 days is ____________________.

Shapley found the distance to the center of the galaxy by studying the distance to open clusters.

Giant molecular cloud complexes are located in spiral arms.

____________________ are groups of 100,000 to 1,000,000 population II stars firmly bound by gravity.

Discuss how Harlow Shapley determined the structure of the Milky Way galaxy from his study of globular clusters.

Nucleosynthesis

In the edge-on sketch of a spiral galaxy, pick the letter corresponding most nearly to the location of globular clusters.

The center of our galaxy lies in the direction of (but far beyond) the stars in the constellation of

Figure 12-1 -Refer to Figure 12-1. A Type I Cepheid has been located in an open cluster. The period of the Cepheid variable is 30 days and the variables apparent visual magnitude, m, is 10. First, use 12-1 to estimate the absolute visual magnitude, M . Calculate the distance to this open cluster? Hint: d_pc = 10^{(m - M + 5)/5}

Who first used RR Lyrae variable stars to determine distances in our Milky Way Galaxy?

The center of our galaxy lies in the direction of the constellation of

Describe the central 25 pc of our galaxy.

Why are all spiral tracers young?

The rotation curve of the galaxy provides evidence for the existence of the ____________________ which extends beyond the halo of the galaxy.

Spiral tracers tend to be old, luminous stars.

Pulsating variable stars are useful in determining

Old stars are poor in heavy elements because there were very few previous generations of stars before the old stars formed.

The traditional "top-down" hypothesis of the formation of our galaxy cannot explain