29:62 GENERAL ASTRONOMY
Fourth Homework Set...Due February 24, 1999

Show calculations and give reasons for your answers. A couple of additional sentences of clarification and explanation may convince the grader you know what you are doing.

1. Prove to me that Sirius is a Main Sequence star. Cite your data and describe how you are using it.
2. What is the upper limit (maximum value a quantity can have) of the age of Sirius?
3. Look at Figure 19-12 in your textbook. Estimate the ages of the Pleiades and M67.
4. The star Gemini (indicated on your SC1 star charts) is a Cepheid variable (read about them in the textbook) with a period of 10.15 days. How bright would it appear at the distance of the Andromeda galaxy M31?
5. Look at Figure 19-15 of your textbook. Estimate the age of the star cluster M3. Note: This is not simply a problem involving plugging in the numbers. You have to do some thinking and perhaps collection of information from a couple of other places in the book. Clearly describe what you are doing and what type of information you are using.

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