1. d) At some point, these stars will run out of fuel, become red giants, and die. When that happens, they move off the Main Sequence, to the right, and land on the “red giant branch.” Let’s focus only on the Main Sequence right now and ignore the rest of the diagram. Let’s assume that all the stars on the Main Sequence in this HR diagram were born at the same time. After 300 million years, the A stars will begin to die and will leave the Main Sequence. Any star more massive than an A star will also have died at this point, because more massive stars die quicker. Draw a vertical line where the Main Sequence ends, after 300 million years have passed. There will be no more stars to the left of this line on the Main Sequence after 300 million years. Do the same for 10 billion years and 100 billion years.

2. Referencing the previous question, if a star on the Main Sequence has a temperature of 3,000 K, predict what its luminosity would be, in solar luminosities (L_¤).

3.  

Luminosity 100000 10000 1000 100 10 0.1 0.01 0.001 0.0001 0.00001 bu LLLL D 30,000 The H-R Diagram of the Nearest and Brightest Stars perpeng x |||| T I 10,000 ---+ Temperature 1 I IDI S0 DO DO 3,000 I 1 1