Question 1

A star's apparent magnitude is a measure of

Accepted Answer

A)  how bright it appears to us if it is at its actual distance.
B)  how bright it appears to us at a standard distance of 10 pc.
C)  its energy output per second compared to the Sun.
D)  its mass in solar masses.
E)  its surface temperature in Kelvin.

Question 2

For what kinds of stars are the masses of stars in the H-R diagram "orderly" For what kinds of stars are they disorderly In other words, could you guess the mass of a star from its location (luminosity, temperature) on the H-R diagram

Accepted Answer

The masses of main-sequence st...

Question 3

Absolute visual magnitude is

Accepted Answer

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)  the apparent magnitude of a star observed from a distance of 10 pc and the luminosity of a star observed from Earth.

Question 4

We know that the numbers of stars _________ from _______ to ________ on the H-R diagram.

Accepted Answer

A)  increases, upper right, lower left
B)  decreases, upper left, lower right
C)  increases, upper left, lower right
D)  decreases, upper right, lower left

Question 5

How do absolute visual magnitude and luminosity differ

Accepted Answer

Absolute visual magnitude of a star is t...

Question 6

Which statement is incorrect about the above spectra

Accepted Answer

A)  Hα line strength increases with decreasing stellar surface temperature from 05 to about F0 and decreases in line strength with decreasing stellar surface temperature from about F0 to M0.
B)  Hβ line strength increases with decreasing stellar surface temperature from 05 to about A1 and decreases in line strength with decreasing stellar surface temperature from about A1 to K0.
C)  Hγ line strength increases with decreasing stellar surface temperature from 05 to about K0 and decreases in line strength with decreasing stellar surface temperature from about K0 to M5.
D)  Hδ line strength increases with decreasing stellar surface temperature from 05 to about A1 and decreases in line strength with decreasing stellar surface temperature from about A1 to K0.

Question 7

Parallax would be easier to measure if

Accepted Answer

A)  Earth's orbit was larger.
B)  the stars were farther away.
C)  Earth moved faster along its orbit.
D)  Earth's orbit was larger, the stars were further away, and Earth moved faster along its orbit.
E)  None of the other choices are correct.

Question 8

We know the white dwarf star Sirius B has a mass comparable to the Sun because

Accepted Answer

A)  of its measured color.
B)  of its measured temperature compared to Sirius A.
C)  it is part of binary star system with Sirius A.

Question 9

The method of spectroscopic parallax cannot be applied to stars beyond about 100 pc.

Accepted Answer

A) True 
 B)False

Question 10

If a star is located at 10 pc, which of the following statements is correct

Accepted Answer

A)  The star's apparent and absolute visual magnitudes are equal.
B)  The star's apparent and absolute visual magnitudes are 0.
C)  The star's apparent visual magnitude is -1.1 whereas the absolute visual magnitude is -5.
D)  Two of the other choices are correct.

Question 11

Main-sequence stars have about the same density as the Sun but giant stars have very low densities.

Accepted Answer

A) True 
 B)False

Question 12

What is the correct order of densities from least to most

Accepted Answer

A)  supergiant, main sequence, white dwarf
B)  main sequence, white dwarf, supergiant
C)  white dwarf, main sequence, giant
D)  main sequence, giant, supergiant

Question 13

How do the spectra of giants, supergiants, and main-sequence stars differ

Accepted Answer

Supergiants have very narrow s...

Question 14

A star's luminosity depends only on the star's

Accepted Answer

A)  distance and diameter.
B)  temperature and distance.
C)  distance.
D)  temperature and diameter.
E)  apparent magnitude.

Question 15

Arcturus has an mV = -0.04 and MV = -0.3. Its distance is 10-3.4 pc.

Accepted Answer

A) True 
 B)False

Question 16

The best sample of the true numbers of the different types of stars consists of

Accepted Answer

A)  stars that appear brightest in the sky to an observer on Earth.
B)  all of the stars within our solar system.
C)  all the stars within a given distance from Earth.

Question 17

Proxima Centauri has an absolute visual magnitude of 15.5 and an apparent visual magnitude of 11.0. What is the distance to Proxima Centauri in units of pc

Accepted Answer

A)  0.1
B)  100.1
C)  10-0.1
D)  None of the other choices are correct.

Question 18

Some giants and/or supergiants are less dense than air.

Accepted Answer

A) True 
 B)False

Question 19

Why don't we see hydrogen Balmer lines in the spectra of stars with temperatures of 3,200 K

Accepted Answer

A)  There is no hydrogen in stars this cool.
B)  The stars are hot enough that most of the hydrogen is ionized and the atoms cannot absorb energy.
C)  These stars are so cool that nearly all of the hydrogen atoms are in the ground state.
D)  Stars of this temperature are too cool to produce an absorption spectrum.
E)  Stars of this temperature are too hot to produce an absorption spectrum.

Question 20

The diagram below illustrates two stars in a visual binary system and the center of mass of this system. Based on this diagram, what is the ratio of the mass of star A to the mass of star B

Accepted Answer

A)  2 to 1
B)  1 to 2
C)  2 to 3
D)  3 to 2
E)  1 to 3

Exam 8: The Family of Stars

A star's apparent magnitude is a measure of

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Some giants and/or supergiants are less dense than air.

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The diagram below illustrates two stars in a visual binary system and the center of mass of this system. Based on this diagram, what is the ratio of the mass of star A to the mass of star B

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Proxima Centauri has an absolute visual magnitude of 15.5 and an apparent visual magnitude of 11.0. What is the distance to Proxima Centauri in units of pc

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How do the spectra of giants, supergiants, and main-sequence stars differ

Correct AnswerverifiedSupergiants have very narrow s...View AnswerShow Answer

Which statement is incorrect about the above spectra

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Why don't we see hydrogen Balmer lines in the spectra of stars with temperatures of 3,200 K

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If a star is located at 10 pc, which of the following statements is correct

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How do absolute visual magnitude and luminosity differ

Correct AnswerverifiedAbsolute visual magnitude of a star is t...View AnswerShow Answer

We know the white dwarf star Sirius B has a mass comparable to the Sun because

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The best sample of the true numbers of the different types of stars consists of

Correct AnswerverifiedShow Answer

What is the correct order of densities from least to most

Correct AnswerverifiedShow Answer

We know that the numbers of stars _________ from _______ to ________ on the H-R diagram.

Correct AnswerverifiedShow Answer

Absolute visual magnitude is

Correct AnswerverifiedShow Answer

A star's luminosity depends only on the star's

Correct AnswerverifiedShow Answer

Main-sequence stars have about the same density as the Sun but giant stars have very low densities.

Correct AnswerverifiedShow Answer

The method of spectroscopic parallax cannot be applied to stars beyond about 100 pc.

Correct AnswerverifiedShow Answer

Parallax would be easier to measure if

Correct AnswerverifiedShow Answer

Arcturus has an mV = -0.04 and MV = -0.3. Its distance is 10-3.4 pc.

Correct AnswerverifiedShow Answer

For what kinds of stars are the masses of stars in the H-R diagram "orderly" For what kinds of stars are they disorderly In other words, could you guess the mass of a star from its location (luminosity, temperature) on the H-R diagram

Correct AnswerverifiedThe masses of main-sequence st...View AnswerShow Answer

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Supergiants have very narrow s...
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Absolute visual magnitude of a star is t...
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We know that the numbers of stars _____ from _ to ______ on the H-R diagram.

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The masses of main-sequence st...
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