Transcript
The Family of Stars
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____ 1. The hydrogen lines in spectral type A stars
a.
are most narrow for supergiants.
b.
are most narrow for main sequence stars.
c.
cannot be used to estimate the luminosity of the star.
d.
are very weak and difficult to see.
e.
are useful in determining the apparent magnitude of the star.
____ 2. Parallax would be easier to measure if
a.
Earth's orbit were larger.
b.
the stars were farther away.
c.
Earth moved slower along its orbit.
d.
all of these
e.
none of these
____ 3. Absolute visual magnitude is
a.
the apparent magnitude of a star observed from Earth.
b.
the luminosity of a star observed from a distance of 1000 pc.
c.
the apparent magnitude of a star observed from a distance of 10 pc.
d.
the luminosity of a star observed from Earth.
e.
c and d
____ 4. A star's absolute magnitude depends only on the star's
a.
distance and diameter.
b.
temperature and distance.
c.
distance.
d.
temperature and diameter.
e.
apparent magnitude.
____ 5. In an H-R Diagram, stars with the smallest radius are found in the _______________ of the diagram.
a.
center
b.
upper left corner
c.
upper right corner
d.
lower left corner
e.
lower right corner
____ 6. In the H-R diagram, 90 percent of all stars are
a.
in the giant region.
b.
in the supergiant region.
c.
among the B stars.
d.
among the G stars.
e.
on the main sequence.
____ 7. We know that giant stars are larger in diameter than the sun because
a.
they are more luminous but have about the same temperature.
b.
they are less luminous but have about the same temperature.
c.
they are hotter but have about the same luminosity.
d.
they are cooler but have about the same luminosity.
e.
they have a larger absolute magnitude than the sun.
____ 8. Giant stars are
I.
more luminous than the sun.
II.
larger in diameter than the sun.
III.
Cooler than B stars.
IV.
located above the main sequence stars in the H-R diagram.
a.
I & II
b.
II & IV
c.
I, II, & IV
d.
II, III, & IV
e.
I, II, III, & IV
____ 9. Compared with the spectral lines in the solar spectrum, lines in a supergiant spectrum are
a.
sharper.
b.
broader.
c.
weaker.
d.
stronger.
e.
b & c
____ 10. The most common stars are
a.
supergiants.
b.
giants.
c.
upper main sequence stars.
d.
white dwarfs.
e.
lower main sequence stars.
____ 11. The _______________ of a star is a measure of the total energy radiated by the star in one second.
a.
absolute visual magnitude
b.
apparent visual magnitude
c.
luminosity class
d.
spectral type
e.
luminosity
____ 12. Sheat is an M2 II star. Based on this information which of the following are true?
I.
Sheat has a surface temperature less than the sun.
II.
Sheat has a diameter that is greater than that of the sun.
III.
Sheat is more luminous than the sun.
IV.
Sheat is located near the upper left hand corner in the HR diagram.
a.
I & II
b.
II & IV
c.
II, III, & IV
d.
I, II, & III
e.
I, II, III, & IV
____ 13. Vega is an A0 V star. Based on this information which of the following are true?
I.
Vega has a surface temperature less than the sun.
II.
Vega has a mass that is greater than that of the sun.
III.
Vega is more luminous than the sun.
IV.
Vega is located near the upper left hand corner in the HR diagram.
a.
I & II
b.
II & III
c.
II, III, & IV
d.
I, II, & III
e.
I, II, III, & IV
____ 14. Groombridge 34 is an M1 V star. Based on this information, which of the following are true?
I.
Groombridge 34 has a surface temperature that is less than the sun.
II.
Groomgridge 34 has a mass that is greater than that of the sun.
III.
Groombridge 34 is less luminous than the sun.
IV.
Groombridge 34 is located near the middle of the HR diagram.
a.
I & II
b.
II & IV
c.
I & IV
d.
I & III
e.
II & III
____ 15. The absolute visual magnitude is most nearly equal to the absolute bolometric magnitude for
a.
stars that radiate most of their energy at visible wavelengths.
b.
spectral type M stars.
c.
spectral type O and B stars.
d.
supergiant and giant stars.
e.
main sequence stars.
____ 16. The distance to Rigel is 250 pc. Which of the following statements is true based on this information?
a.
The distance to Rigel can be determined by measuring its parallax.
b.
Rigel's apparent visual magnitude has a smaller value than its absolute visual magnitude.
c.
The absolute bolometric magnitude of Rigel is nearly equal to its absolute visual magnitude.
d.
Rigel is located in the upper right corner of the HR diagram.
e.
none of the above
____ 17. The star Sadir has an absolute bolometric magnitude of -5.3 and the absolute bolometric magnitude of the sun is +4.7. Based on this information, which of the following statements is true.
a.
Sadir has a greater surface temperature than the sun.
b.
Sadir has a larger diameter than the sun.
c.
Sadir is 10,000 times more luminous than the sun.
d.
Sadir is 100 parsecs from Earth.
e.
all of the above
HR Diagram
____ 18. Which star in the HR Diagram above is most like the sun?
a.
Alnilam
b.
Antares
c.
Arcturus
d.
HR 5337
e.
Sirius B
____ 19. Which star in the HR Diagram above has the greatest surface temperature?
a.
Alnilam
b.
Antares
c.
Arcturus
d.
HR 5337
e.
Sirius B
____ 20. Which of the stars in the HR Diagram above has the largest absolute visual magnitude?
a.
Alnilam
b.
Antares
c.
Arcturus
d.
HR 5337
e.
Sirius B
____ 21. If a star has a parallax of 0.02 seconds of arc, then its distance will be
a.
20 pc
b.
50 pc
c.
2 pc
d.
5 pc
e.
500 pc
____ 22. If a star with an absolute magnitude of -5 has an apparent magnitude of +5, then its distance is
a.
1 pc.
b.
10 pc.
c.
100 pc.
d.
1000 pc
e.
10,000 pc.
Star Table
Star
m v
M v
d (pc)
Parallax
(sec of arc)
Spectral
Type
65 Tau
4.2
0.025
A7 IV
HR 4621
2.6
-0.3
B2 IV
Pic
1.8
20
A7 V
58 Ori
-6.0
0.005
M2 I
HR 2491
-1.5
2.5
A1 V
____ 23. Which star in the Star Table above would appear the faintest in the night sky?
a.
65 Tau
b.
HR 4621
c.
Pic
d.
58 Ori
e.
HR 2491
____ 24. Which star in the Star Table above has the greatest luminosity?
a.
65 Tau
b.
HR 4621
c.
Pic
d.
58 Ori
e.
HR 2491
____ 25. Which star in the Star Table above is the closest to Earth?
a.
65 Tau
b.
HR 4621
c.
Pic
d.
58 Ori
e.
HR 2491
____ 26. Which star in the Star Table above has the greatest surface temperature?
a.
65 Tau
b.
HR 4621
c.
Pic
d.
58 Ori
e.
HR 2491
____ 27. Which star in the Star Table above has the greatest diameter?
a.
65 Tau
b.
HR 4621
c.
Pic
d.
58 Ori
e.
HR 2491
True/False
Indicate whether the sentence or statement is true or false.
____ 28. A star whose parallax is 0.01 seconds of arc is at a distance of 1,000 pc.
____ 29. The absolute magnitude of a star is the apparent magnitude it would have if it were 10 pc from Earth.
____ 30. The location of a star in the HR diagram indicates its temperature and intrinsic brightness.
____ 31. Lines in the spectra of supergiant stars are broader than the same spectral lines in main sequence stars of the same spectral type.
____ 32. Giant stars are members of luminosity class III.
____ 33. If a star is twice as hot as the sun and only half the sun's diameter, it will be less luminous than the sun.
____ 34. The method of spectroscopic parallax cannot be applied to stars beyond about 100 pc.
____ 35. The most common kinds of stars are low-luminosity stars.
____ 36. Supergiants are about as common as the sun.
____ 37. White dwarfs have such a low luminosity that even the nearest white dwarfs are not visible to the naked eye.
Answer Section
MULTIPLE CHOICE
1. ANS: A
2. ANS: A
3. ANS: C
4. ANS: D
5. ANS: D
6. ANS: E
7. ANS: A
8. ANS: E
9. ANS: A
10. ANS: E
11. ANS: E
12. ANS: D
13. ANS: B
14. ANS: D
15. ANS: A
16. ANS: E
17. ANS: C
18. ANS: D
19. ANS: A
20. ANS: E
21. ANS: B
22. ANS: D
23. ANS: A
24. ANS: D
25. ANS: E
26. ANS: B
27. ANS: D
TRUE/FALSE
28. ANS: F
29. ANS: T
30. ANS: T
31. ANS: F
32. ANS: T
33. ANS: F
34. ANS: F
35. ANS: T
36. ANS: F
37. ANS: T
