Question 1

What is stellar parallax and what stellar property can you determine from it?

Accepted Answer

Stellar parallax is the most straightfor...

Question 2

If stellar parallax can be measured to a precision of about 0.01 arcsec using telescopes on Earth to observe stars,to what distance does this correspond in space?

Accepted Answer

A)   500 pc
B)   200 pc
C)   100 pc
D)   0.01 pc

Question 3

Red stars are relatively cool compared with other stars,with low surface temperatures.

Accepted Answer

A) True 
 B)False

Question 4

Star A has a luminosity LA = 100 L and it is 1000 pc away.Star B has the same luminosity as the Sun,L,and it is 100 pc away.What can you say about the brightness of these two stars?

Accepted Answer

A)   Star A is brighter than Star B.
B)   Star B is brighter than Star A.
C)   Star A and Star B have the same brightness.
D)   It is not possible to determine the answer without knowing L,the luminosity of the Sun.

Question 5

Stars of spectral type O,the hottest blue-white stars,have spectra characterized by

Accepted Answer

A)   the strongest hydrogen lines of any spectral type.
B)   spectra of complex molecules.
C)   very few spectral lines.
D)   very intense spectral lines all across the spectrum.

Question 6

In the spectral classification of stars,strong absorption lines of which of the following atomic or molecular constituents would indicate very low surface temperature?

Accepted Answer

A)   He II
B)   Fe II
C)   Mg II
D)   TiO

Question 7

If two stars of different luminosity have the same temperature,a luminosity class III star will be smaller than a luminosity class I star.

Accepted Answer

A) True 
 B)False

Question 8

The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it

Accepted Answer

A)   is brighter than Megrez,as seen in our sky.
B)   has a greater luminosity than Megrez.
C)   is closer than Megrez.
D)   is fainter than Megrez,as seen in our sky.

Question 9

If the mass of a main-sequence star is greater than another,the

Accepted Answer

A)   luminosity would also be greater.
B)   surface temperature would also be greater.
C)   radius would also be greater.
D)   luminosity,the surface temperature,and the radius would also be greater.

Question 10

How do you find the size of a star?

Accepted Answer

You can find a star's radius from its lu...

Question 11

Two stars have the same spectral classification,say M2,but one is a red giant and the other is a main-sequence star.To determine which is which,we look at their spectra because the absorption lines in the giant will be

Accepted Answer

A)   narrower because of the pressure-broadening effect.
B)   broader because of the pressure-broadening effect.
C)   narrower because of the temperature difference between the two luminosity classes.
D)   broader because of the temperature difference between the two luminosity classes.

Question 12

By analyzing a star's spectra,the chemical composition,the spectral type,and the luminosity class can be determined.

Accepted Answer

A) True 
 B)False

Question 13

As you move upward and to the left on the H-R diagram,the stars become

Accepted Answer

A)   cooler and redder.
B)   hotter and redder.
C)   cooler and whiter.
D)   hotter and whiter.

Question 14

If a star were 25 parsecs away,it would have a parallax of how many arcseconds?

Accepted Answer

A)   0.04
B)   0.25
C)   4
D)   25

Question 15

What is the difference between absolute magnitude and apparent magnitude?

Accepted Answer

Apparent magnitude is how bright a star ...

Question 16

The relative brightness of stars as we see them in our sky are represented on star charts in terms of their

Accepted Answer

A)   surface temperatures.
B)   absolute magnitudes.
C)   apparent magnitudes.
D)   luminosities.

Question 17

The relationship between mass and luminosity of stars on the main sequence is that

Accepted Answer

A)   the luminosity of stars rises to a peak at around a mass of 1 solar mass and decreases as mass increases beyond this limit.
B)   the greater the stellar mass,the larger the luminosity.
C)   luminosity is independent of the stellar mass.
D)   the greater the stellar mass,the less the luminosity.

Question 18

An important aspect of binary star systems,as distinct from single stars,is that they allow a

Accepted Answer

A)   verification of the Doppler shift.
B)   measurement of the overall shapes of stars.
C)   measurement of the universal gravitational constant.
D)   measurement of the masses of stars.

Question 19

Which of the following atoms or ions will produce strong absorption lines in the spectra of stars with relatively cool surface temperatures?

Accepted Answer

A)   TiO,molecules of titanium oxide
B)   He I,neutral helium
C)   Mg II,ionized magnesium
D)   Ca II,ionized calcium

Question 20

The point around which two stars of unequal mass in a binary system appear to revolve is

Accepted Answer

A)   closest to the more massive star.
B)   halfway between the two star centers.
C)   at the center of the more massive star.
D)   closest to the less massive star.

Exam 10: Observing Properties of Distant Stars

By analyzing a star's spectra,the chemical composition,the spectral type,and the luminosity class can be determined.

Correct AnswerverifiedShow Answer

The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it

Correct AnswerverifiedShow Answer

Two stars have the same spectral classification,say M2,but one is a red giant and the other is a main-sequence star.To determine which is which,we look at their spectra because the absorption lines in the giant will be

Correct AnswerverifiedShow Answer

An important aspect of binary star systems,as distinct from single stars,is that they allow a

Correct AnswerverifiedShow Answer

In the spectral classification of stars,strong absorption lines of which of the following atomic or molecular constituents would indicate very low surface temperature?

Correct AnswerverifiedShow Answer

If stellar parallax can be measured to a precision of about 0.01 arcsec using telescopes on Earth to observe stars,to what distance does this correspond in space?

Correct AnswerverifiedShow Answer

How do you find the size of a star?

Correct AnswerverifiedYou can find a star's radius from its lu...View AnswerShow Answer

What is stellar parallax and what stellar property can you determine from it?

Correct AnswerverifiedStellar parallax is the most straightfor...View AnswerShow Answer

Stars of spectral type O,the hottest blue-white stars,have spectra characterized by

Correct AnswerverifiedShow Answer

The relative brightness of stars as we see them in our sky are represented on star charts in terms of their

Correct AnswerverifiedShow Answer

As you move upward and to the left on the H-R diagram,the stars become

Correct AnswerverifiedShow Answer

If a star were 25 parsecs away,it would have a parallax of how many arcseconds?

Correct AnswerverifiedShow Answer

Which of the following atoms or ions will produce strong absorption lines in the spectra of stars with relatively cool surface temperatures?

Correct AnswerverifiedShow Answer

Red stars are relatively cool compared with other stars,with low surface temperatures.

Correct AnswerverifiedShow Answer

The point around which two stars of unequal mass in a binary system appear to revolve is

Correct AnswerverifiedShow Answer

If the mass of a main-sequence star is greater than another,the

Correct AnswerverifiedShow Answer

What is the difference between absolute magnitude and apparent magnitude?

Correct AnswerverifiedApparent magnitude is how bright a star ...View AnswerShow Answer

If two stars of different luminosity have the same temperature,a luminosity class III star will be smaller than a luminosity class I star.

Correct AnswerverifiedShow Answer

The relationship between mass and luminosity of stars on the main sequence is that

Correct AnswerverifiedShow Answer

Star A has a luminosity LA = 100 L and it is 1000 pc away.Star B has the same luminosity as the Sun,L,and it is 100 pc away.What can you say about the brightness of these two stars?

Correct AnswerverifiedShow Answer

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You can find a star's radius from its lu...
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Stellar parallax is the most straightfor...
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Apparent magnitude is how bright a star ...
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Star A has a luminosity L_A = 100 L and it is 1000 pc away.Star B has the same luminosity as the Sun,L,and it is 100 pc away.What can you say about the brightness of these two stars?

Correct Answer
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