Question 1

When helium fusion begins in the core of a red giant star, the situation quickly gets out of control because electron-degeneracy pressure does not respond to changes in

Accepted Answer

A)   luminosity.
B)   density.
C)   gravity.
D)   temperature.
E)   magnetic field strength.F) A) and E)
G) B) and E)

Question 2

How long will a 2 MSUN star live as a main-sequence star?

Accepted Answer

A)   12 million years
B)   180 million years
C)   1.8 billion years
D)   12 billion years
E)   18 billion yearsF) A) and D)
G) All of the above

Question 3

A 1-MSUN star in a binary system could eventually create which chemical element and eject it into the interstellar medium?

Accepted Answer

A)   carbon
B)   helium
C)   iron
D)   all of these
E)   none of theseF) C) and D)
G) B) and D)

Question 4

A feature unique to main-sequence stars is that

Accepted Answer

A)   hydrostatic equilibrium exists at all radii.
B)   energy transport occurs via convection throughout much of their interiors.
C)   carbon burning occurs in their cores.
D)   they emit strong surface winds.
E)   hydrogen burning occurs in their cores.F) B) and E)
G) B) and C)

Question 5

What is a planetary nebula, and why are many planetary nebulae not symmetrical?

Accepted Answer

A planetary nebula is formed when the ou...

Question 6

Place the evolutionary stages shown in the figure below in order from earliest to latest.

Accepted Answer

A)   1, 2, 3
B)   2, 3, 1
C)   3, 2, 1
D)   3, 1, 2
E)   2, 1, 3F) B) and C)
G) None of the above D

Question 7

The main-sequence lifetime of a star is given by which equation?

Accepted Answer

A)   t 2/L 
D)   t   L2/L 
E)   t   M/L2" class="answers-bank-image d-inline" rel="preload" > M/L
B)   t 2/L 
D)   t   L2/L 
E)   t   M/L2" class="answers-bank-image d-inline" rel="preload" > L/M
C)   t 2/L 
D)   t   L2/L 
E)   t   M/L2" class="answers-bank-image d-inline" rel="preload" > M 2/L
D)   t 2/L 
D)   t   L2/L 
E)   t   M/L2" class="answers-bank-image d-inline" rel="preload" > L2/L
E)   t 2/L 
D)   t   L2/L 
E)   t   M/L2" class="answers-bank-image d-inline" rel="preload" > M/L2F) A) and D)
G) A) and B) A

Question 8

Describe the similarities and differences between the helium flash in the core of a red giant star and the explosive hydrogen burning on the surface of a white dwarf star.

Accepted Answer

In the red giant core,degenerate electro...

Question 9

The low-end mass cutoff for stars occurs at approximately

Accepted Answer

A)   0.08 MSUN.
B)   0.1 MSUN.
C)   0.8 MSUN.
D)   1 MSUN.
E)   10 MSUN.F) B) and D)
G) B) and C)

Question 10

Considering their lifetimes, which types of main-sequence stars would be more likely to have planets with complex life?

Accepted Answer

Low-mass main-sequence stars have longer...

Question 11

What types of chemical elements can low-mass stars contribute to the enrichment of the interstellar medium and how are they produced?

Accepted Answer

Low-mass stars can enrich the interstell...

Question 12

During evolutionary phase A in the figure shown below, the star is ________.In evolutionary phase B, it is ________.

Accepted Answer

A)   expanding; expanding
B)   expanding; contracting
C)   contracting; losing mass
D)   contracting; contracting
E)   gaining mass; contractingF) A) and D)
G) B) and D)

Question 13

As a low-mass main-sequence star runs out of fuel in its core, it grows more luminous. How is this possible?

Accepted Answer

A)   It explodes.
B)   It begins to fuse helium in the core.
C)   The core expands as it runs out of fuel.
D)   The core shrinks, bringing more hydrogen fuel into the fusing region.
E)   Convection takes place throughout the interior, bringing more fuel to the core.F) A) and E)
G) C) and D)

Question 14

A 10 MSUN star will evolve through the same phases as a

Accepted Answer

A)   1 MSUN star.
B)   5 MSUN star.
C)   20 MSUN star.
D)   0.5 MSUN star.
E)   0.08 MSUN star.F) A) and E)
G) B) and C)

Question 15

When matter is packed so tightly together that quantum physics will not allow the electrons to get any closer, it is called

Accepted Answer

A)   electron-degenerate.
B)   neutron-degenerate
C)   nucleon-degenerate.
D)   quantum-limited.
E)   exotic matter.F) A) and B)
G) A) and C)

Question 16

When the Sun becomes an AGB star, its radius will be approximately 100 RSUN.If its mass at this point will be approximately the same as it is now, how will its surface gravity as an AGB star compare to its present surface gravity as a main-sequence star? (Note that g =GM/R2.)

Accepted Answer

Surface gravity: g = GM/R² *g...

Question 17

The core of an asymptotic giant branch star is filled with

Accepted Answer

A)   hydrogen gas.
B)   electron-degenerate hydrogen.
C)   helium gas.
D)   electron-degenerate helium.
E)   electron-degenerate carbon.F) D) and E)
G) None of the above

Question 18

A star's surface temperature during the horizontal branch phase is determined primarily by its

Accepted Answer

A)   luminosity.
B)   mass and chemical composition.
C)   magnetic field strength.
D)   rotation rate.
E)   radius.F) C) and E)
G) A) and E) B

Question 19

What is a white dwarf star, and what are the major properties of such a star?

Accepted Answer

A white dwarf star is a tiny (Earth-size...

Question 20

How can the core of a star be degenerate with respect to the electrons but nondegenerate with respect to the nuclei?

Accepted Answer

(1)Quantum mechanics says electrons take...

Exam 16: Evolution of Low-Mass Stars

When helium fusion begins in the core of a red giant star, the situation quickly gets out of control because electron-degeneracy pressure does not respond to changes in

Correct AnswerverifiedShow Answer

How long will a 2 MSUN star live as a main-sequence star?

Correct AnswerverifiedShow Answer

A 1-MSUN star in a binary system could eventually create which chemical element and eject it into the interstellar medium?

Correct AnswerverifiedShow Answer

A feature unique to main-sequence stars is that

Correct AnswerverifiedShow Answer

What is a planetary nebula, and why are many planetary nebulae not symmetrical?

Correct AnswerverifiedA planetary nebula is formed when the ou...View AnswerShow Answer

Place the evolutionary stages shown in the figure below in order from earliest to latest.

Correct AnswerverifiedD

The main-sequence lifetime of a star is given by which equation?

Correct AnswerverifiedA

Describe the similarities and differences between the helium flash in the core of a red giant star and the explosive hydrogen burning on the surface of a white dwarf star.

Correct AnswerverifiedIn the red giant core,degenerate electro...View AnswerShow Answer

The low-end mass cutoff for stars occurs at approximately

Correct AnswerverifiedShow Answer

Considering their lifetimes, which types of main-sequence stars would be more likely to have planets with complex life?

Correct AnswerverifiedLow-mass main-sequence stars have longer...View AnswerShow Answer

What types of chemical elements can low-mass stars contribute to the enrichment of the interstellar medium and how are they produced?

Correct AnswerverifiedLow-mass stars can enrich the interstell...View AnswerShow Answer

During evolutionary phase A in the figure shown below, the star is ________.In evolutionary phase B, it is ________.

Correct AnswerverifiedShow Answer

As a low-mass main-sequence star runs out of fuel in its core, it grows more luminous. How is this possible?

Correct AnswerverifiedShow Answer

A 10 MSUN star will evolve through the same phases as a

Correct AnswerverifiedShow Answer

When matter is packed so tightly together that quantum physics will not allow the electrons to get any closer, it is called

Correct AnswerverifiedShow Answer

When the Sun becomes an AGB star, its radius will be approximately 100 RSUN.If its mass at this point will be approximately the same as it is now, how will its surface gravity as an AGB star compare to its present surface gravity as a main-sequence star? (Note that g =GM/R2.)

Correct AnswerverifiedSurface gravity: g = GM/R2 *g...View AnswerShow Answer

The core of an asymptotic giant branch star is filled with

Correct AnswerverifiedShow Answer

A star's surface temperature during the horizontal branch phase is determined primarily by its

Correct AnswerverifiedB

What is a white dwarf star, and what are the major properties of such a star?

Correct AnswerverifiedA white dwarf star is a tiny (Earth-size...View AnswerShow Answer

How can the core of a star be degenerate with respect to the electrons but nondegenerate with respect to the nuclei?

Correct Answerverified(1)Quantum mechanics says electrons take...View AnswerShow Answer

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How long will a 2 M_SUN star live as a main-sequence star?

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A 1-M_SUN star in a binary system could eventually create which chemical element and eject it into the interstellar medium?

Correct Answer
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A planetary nebula is formed when the ou...
View Answer

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D

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A

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In the red giant core,degenerate electro...
View Answer

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Low-mass main-sequence stars have longer...
View Answer

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Low-mass stars can enrich the interstell...
View Answer

During evolutionary phase A in the figure shown below, the star is .In evolutionary phase B, it is .

Correct Answer
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A 10 M_SUNstar will evolve through the same phases as a

Correct Answer
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When the Sun becomes an AGB star, its radius will be approximately 100 R_SUN.If its mass at this point will be approximately the same as it is now, how will its surface gravity as an AGB star compare to its present surface gravity as a main-sequence star? (Note that g =GM/R².)

Correct Answer
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Surface gravity: g = GM/R² *g...
View Answer

Correct Answer
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B

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A white dwarf star is a tiny (Earth-size...
View Answer

Correct Answer
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(1)Quantum mechanics says electrons take...
View Answer