NAME
ASTRONOMY 162 Section 2 TEST 2: April 5, 2018
E = mc^2 c = 300,000 km/sec E/A = a T^4
r = 1/p" v = f wavelength(max) = 3000/T
part 1: 3 points for each multiple choice question. Do not forget to put your name on the test
1. More massive stars have, compared to our Sun,
a) shorter lifetimes
b) a larger rate of H to He fusion
c) hotter surface and core temperatures
d) all of the above
2. Two stars have the same radius but star A has a surface temperature of 5000 degrees K while star B has a surface temperature of 15,000 degrees K. Star B will have
a) more electromagnetic radiation in the UV than star A
b) always have a larger absolute luminosity than star A
c) sometimes have a smaller and sometime have a larger apparent luminosity than star A
d) all of the above
3. The gravitational pull in the centers of highly evolved Red Giants
is resisted by the pressure due to
a) the weak nuclear force
b) helium atoms
c) the interstellar medium
d) degenerate electrons
4. The study of the motion of the two stars in a binary star system about each other allows a measurement of the stars’
a) lifetimes
b) distances from us
c) masses
d) planets
5. Carbon and oxygen in our Universe are primarily made by
a) H fusion in main sequence stars
b) proton conversions in neutron stars
c) He fusion in giant stars
d) during supernova explosions
6. A star which is 10 times further away than an identical star will have
a) an absolute luminosity 1/10 the closer star
b) an apparent luminosity 1/10 the closer star
c) an apparent luminosity 1/100 the closer star
d) the same apparent luminosity
7. A white dwarf is about the size of
a) DeKalb County
b) Jupiter
c) the Earth
d) the Sun
Section 2: Answer the following questions about the H-R plot on this page. 3 pts each
The answer is always “of the stars listed in the question” and not all the stars
8. The ratio of the radius of star 8 to the radius of star 3 is about
a) 3 b) 10000 c) 60 d) 100 e) 1000
9. Which star has the hottest surface temperature?
a) 2 b) 7 c) 7 d) 6 e) 10
10. Which main sequence star is most likely to become a supernova?
a) 1 b) 3 c) 5 d) 8 e) 4
11. Which star has the largest radius?
a) 7 b) 6 c) 1 d) 9 e) 10
12. Which star has the smallest radius?
a) 10 b) 1 c) 7 d) 3 e) 5
13. Which main sequence star will live the longest?
a) 5 b) 2 c) 3 d) 10 e) 8
14. Which star is a Red Giant?
a) 9 b) 10 c) 6 d) 3 e) 5
15. Which main sequence star will live about 10 billion years?
a) 4 b) 8 c) 6 d) 2 e) 3
16. Which star has the coolest surface temperature?
a) 10 b) 1 c) 8 d) 6 e) 5
17. Which star has the highest absolute luminosity?
a) 4 b) 5 c) 10 d) 7 e) 6
18. Which main sequence star will become a Red Giant?
a) 7 b) 5 c) 9 d) 10 e) 3
Page 3
19. Describe the most interesting thing you learned in Section 2 of this course covering all aspects of stars. 10 points
Answer 3 out of 4. If you answer more than three only the first threecount. 12 pts each
20. Describe the steps leading to the formation of a main sequence star like our Sun.
21. Describe the differences between a white dwarf, a neutron star, and a black hole including how they are formed.
22. Describe the steps leading to EITHER a Type Ia ORa Type II supernova, what happens during the supernova, and what is leftover.
23. Explain how to measure the distance to a nearby star that is a star within 500 LY.