Homework Question Set 5 -- Due Oct 16

1) Spica is located about 80 parsecs away. Spica's absolute magnitde is -3.6. Which of the following is most likely Spica's apparent magnitude.
a) -8.1
b) -4.2
c) -3.6
d) +0.9
e) +3.6


2) Suppose that two stars are at equal distance and have the same radius, but one has a temperature that is about twice as great as the other. The flux from the hotter star is
about 16 times less
about 16 times greater
c) about 20 percent greater
d) about 200 percent less
e) there is not enough information to answer the question.


3) The most important property in determining the eventual fate of a star is
its chemical composition
its mass
the initial concentration of iron in its core
none of the above


4) An eclipsing binary is composed of a main sequence A-star and a K-type giant star. When will we see minimum light? (Hint: try to draw a picture of what's happening and then use your knowledge of the blackbody law.)
a) Minimum light will occur when the K-star is in front of the A-star.
b) Minimum light will occur when the A-star is in front of the K-star.
c) The depth of the two eclipses will be equal -- minimum light will occur when either star is in front of the other.


5) A main sequence O-star and a main sequence M-star form a very close binary system. If there is no dust between you and the system, then the binary will appear
a) blue
b) red
c) yellow
d) green
e) as a spectroscopic binary