Be sure to show your work, do your own work, and put your name and row letter on it and write legibly. If I can't read it, I can't grade it.
Do on your own paper- do not turn in any images.
If an answer is numerical you must show the equation for credit.

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Question 1: About what fraction of stars have planets?
A) Close to 0% (nearly just us)
B) 10%
C) 50%
D) 90%

Question 2: Which star is the coolest?
A) Yellow
B) Red
C) Orange.
D) Violet
E) Blue

Question 3: What is the temperature of a star with a peak in its spectrum at 250 nm?


A cloud collapses to form 4 stars. Star A is 12 solar masses, Star B is 3 solar masses, Star C is 0.8 solar masses and star D is 0.4 solar masses. These stars all begin the main sequence at the same time and would be roughly the same distance from us.

Question 4: Which star is the hottest?

Question 5: Which star is the faintest?

Question 6: What is the total luminosity of these 4 stars (in solar units) on the main sequence?

Question 7: After 3 billion years, how many stars are still on the main sequence?

Question 8: After 15 billion years, how many stars are still on the main sequence?

Question 9: Why must stars evolve?

Question 10: What is the source of energy for our Sun?

Question 11: I see a red star and a blue star in a binary. The red star is brighter, what else do I know about these two stars?


Question 11: How will our Sun end?
A) It will explode (a supernova).
B) It will shine forever.
C) As a white dwarf.
D) As a supergiant.