Question 1

How large will the Sun be as a red giant?

Accepted Answer

A)  about 1 au radius (out to Earth's orbit) 
B)  about 1/10 au radius (1/4 of Mercury's orbit) 
C)  about 1.5 au radius (out to Mars's orbit) 
D)  about 1/2 au radius (beyond Mercury's orbit) 
A)  about 1 au radius (out to Earth's orbit) 
B)  about 1/10 au radius (1/4 of Mercury's orbit) 
C)  about 1.5 au radius (out to Mars's orbit) 
D)  about 1/2 au radius (beyond Mercury's orbit)

Question 2

At what point in its evolution does a protostar stop shrinking and stabilize into a star?

Accepted Answer

A)  when nuclear processes generate enough energy and internal pressure to resist gravitational contraction 
B)  when gravitational contraction has heated up the gas to the point where radiation pressure opposes gravity for the first time 
C)  when the protostar has spun off enough of its matter and is spinning fast enough that centrifugal force opposes the gravitational contraction 
D)  when nuclear reactions end in the star's core 
A)  when nuclear processes generate enough energy and internal pressure to resist gravitational contraction 
B)  when gravitational contraction has heated up the gas to the point where radiation pressure opposes gravity for the first time 
C)  when the protostar has spun off enough of its matter and is spinning fast enough that centrifugal force opposes the gravitational contraction 
D)  when nuclear reactions end in the star's core

Question 3

In star-forming regions in interstellar space, which molecule is the easiest to detect?

Accepted Answer

A)  ammonia (NH3) 
B)  hydrogen (H2) 
C)  formaldehyde (H2CO) 
D)  carbon monoxide (CO) 
A)  ammonia (NH3) 
B)  hydrogen (H2) 
C)  formaldehyde (H2CO) 
D)  carbon monoxide (CO)

Question 4

The process of evolution of stars in the universe has been interpreted by

Accepted Answer

A)  matching theoretical models to the properties of similar stars at different distances from Earth, since more distant stars from an earlier time are observed, when the light left them. 
B)  matching theoretical models to the collective properties, such as luminosity, temperature, and size, of millions of stars as observed. 
C)  designing theoretical models solely on the basis of the known properties of matter, without reference to observational data on real stars, since there is not have a sufficiently long time base for stellar observations. 
D)  matching theoretical models to the detailed observation of a few stars as astronomers watch them change in luminosity, temperature, and size during their evolution. 
A)  matching theoretical models to the properties of similar stars at different distances from Earth, since more distant stars from an earlier time are observed, when the light left them. 
B)  matching theoretical models to the collective properties, such as luminosity, temperature, and size, of millions of stars as observed. 
C)  designing theoretical models solely on the basis of the known properties of matter, without reference to observational data on real stars, since there is not have a sufficiently long time base for stellar observations. 
D)  matching theoretical models to the detailed observation of a few stars as astronomers watch them change in luminosity, temperature, and size during their evolution.

Question 5

Which of these stars could be classified as a Population II star?

Accepted Answer

A)  star with very low abundance of heavy elements 
B)  star in an open star cluster 
C)  star with approximately the same abundance of heavy elements found in the Sun 
D)  star with much higher abundance of heavy elements than found in the Sun 
A)  star with very low abundance of heavy elements 
B)  star in an open star cluster 
C)  star with approximately the same abundance of heavy elements found in the Sun 
D)  star with much higher abundance of heavy elements than found in the Sun

Question 6

Which of these objects is NOT an abundant physical component of the interstellar medium?

Accepted Answer

A)  atoms and ions 
B)  molecules 
C)  dust 
D)  radioactive elements 
A)  atoms and ions 
B)  molecules 
C)  dust 
D)  radioactive elements

Question 7

Which of these properties is a known characteristic of a T Tauri star?

Accepted Answer

A)  ejection of mass into space 
B)  great age, near the end of its life as a star 
C)  high mass, greater than about 3 solar masses 
D)  nuclear reactions in the core 
A)  ejection of mass into space 
B)  great age, near the end of its life as a star 
C)  high mass, greater than about 3 solar masses 
D)  nuclear reactions in the core

Question 8

Which of these objects are NOT very young stars or prestellar objects?

Accepted Answer

A)  red giants 
B)  infrared-emitting stars in gas and dust clouds 
C)  protostars 
D)  T Tauri stars 
A)  red giants 
B)  infrared-emitting stars in gas and dust clouds 
C)  protostars 
D)  T Tauri stars

Question 9

Which one (if any) of these objects is a star in the sense that its main source of energy is nuclear fusion of normal hydrogen?

Accepted Answer

A)  T Tauri star 
B)  sub-brown dwarf 
C)  brown dwarf 
D)  None of these has nuclear fusion as its main energy source. 
A)  T Tauri star 
B)  sub-brown dwarf 
C)  brown dwarf 
D)  None of these has nuclear fusion as its main energy source.

Question 10

To detect most interstellar material requires

Accepted Answer

A)  optical telescopes. 
B)  gamma-ray observatories. 
C)  radio telescopes. 
D)  ultraviolet detectors. 
A)  optical telescopes. 
B)  gamma-ray observatories. 
C)  radio telescopes. 
D)  ultraviolet detectors.

Question 11

What is the minimum mass necessary in a protostar for it to begin hydrogen fusion reactions and become a main-sequence star?

Accepted Answer

A)  0.08 solar masses 
B)  0.4 solar masses 
C)  1.0 solar masses 
D)  1.4 solar masses 
A)  0.08 solar masses 
B)  0.4 solar masses 
C)  1.0 solar masses 
D)  1.4 solar masses

Question 12

What determines whether a particular region of an interstellar cloud can collapse and form a star?

Accepted Answer

A)  temperature, since higher temperatures act to prevent collapse 
B)  amount of gravity pulling inward compared with gas pressure pushing outward 
C)  gas density (the ratio of the mass of the cloud over its volume), since density determines how gravity will act on the cloud material 
D)  amount of mass in the cloud, since mass determines the strength of gravity 
A)  temperature, since higher temperatures act to prevent collapse 
B)  amount of gravity pulling inward compared with gas pressure pushing outward 
C)  gas density (the ratio of the mass of the cloud over its volume), since density determines how gravity will act on the cloud material 
D)  amount of mass in the cloud, since mass determines the strength of gravity

Question 13

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

Accepted Answer

A)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
B)  The star is slowly shrinking as it slides down the main sequence from top left to bottom right across the H-R diagram. 
C)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation. 
D)  The star is generating internal energy by hydrogen fusion. 
A)  The star is generating energy by helium fusion, having stopped hydrogen "burning." 
B)  The star is slowly shrinking as it slides down the main sequence from top left to bottom right across the H-R diagram. 
C)  Stars that have reached the main sequence have ceased nuclear "burning" and are simply cooling down by emitting radiation. 
D)  The star is generating internal energy by hydrogen fusion.

Question 14

The total lifespan of the Sun is believed to be

Accepted Answer

A)  a few million years. 
B)  half a billion years. 
C)  10 billion years. 
D)  infinite. 
A)  a few million years. 
B)  half a billion years. 
C)  10 billion years. 
D)  infinite.

Question 15

What is believed to prevent stars from being larger than a few hundred solar masses?

Accepted Answer

A)  Stars of larger mass would collapse under their own gravity and become black holes. 
B)  No interstellar clouds have masses of more than 100 solar masses. 
C)  The cores of larger-mass stars would run through their lives and explode before the stars finish contracting as protostars. 
D)  The temperature becomes so high that the excess mass is pushed back into space by radiation from the star. 
A)  Stars of larger mass would collapse under their own gravity and become black holes. 
B)  No interstellar clouds have masses of more than 100 solar masses. 
C)  The cores of larger-mass stars would run through their lives and explode before the stars finish contracting as protostars. 
D)  The temperature becomes so high that the excess mass is pushed back into space by radiation from the star.

Question 16

Which of these events does NOT happen in a star in the course of its evolution?

Accepted Answer

A)  buildup of heavy elements from fusion of hydrogen 
B)  loss of mass as radiation 
C)  loss of mass through winds 
D)  buildup of hydrogen from breakdown of heavier elements by fission 
A)  buildup of heavy elements from fusion of hydrogen 
B)  loss of mass as radiation 
C)  loss of mass through winds 
D)  buildup of hydrogen from breakdown of heavier elements by fission

Question 17

How many stars are there in a large globular cluster?

Accepted Answer

A)  about 1 million 
B)  about 1000 
C)  up to 100 billion 
D)  only a few dozen 
A)  about 1 million 
B)  about 1000 
C)  up to 100 billion 
D)  only a few dozen

Question 18

When core helium burning begins in the Sun, the Sun will have a size (radius) roughly equal to

Accepted Answer

A)  half the size of Earth's orbit. 
B)  the size of Earth. 
C)  half its present size. 
D)  twice its present size. 
A)  half the size of Earth's orbit. 
B)  the size of Earth. 
C)  half its present size. 
D)  twice its present size.

Question 19

Which of these conditions does NOT characterize the transition from a pre-main-sequence star to a main-sequence star?

Accepted Answer

A)  The star begins fusing hydrogen into helium in its core. 
B)  The star stops contracting. 
C)  The gas and dust around the pre-main-sequence star largely dissipates. 
D)  Helium burning becomes the principal energy-generating mechanism in the star's core. 
A)  The star begins fusing hydrogen into helium in its core. 
B)  The star stops contracting. 
C)  The gas and dust around the pre-main-sequence star largely dissipates. 
D)  Helium burning becomes the principal energy-generating mechanism in the star's core.

Question 20

For an amateur astronomer to observe some of the more visible nebulae, it is suggested that the instrument to be used is

Accepted Answer

A)  a telescope because very high magnification is needed to resolve even the most visible nebulae. 
B)  binoculars because they have a larger field of view and can allow the whole nebula to be seen. 
C)  binoculars because telescopes tend to wash out the beautiful colors of the nebulae. 
D)  the naked eye because these objects are easily seen when one knows where to look. 
A)  a telescope because very high magnification is needed to resolve even the most visible nebulae. 
B)  binoculars because they have a larger field of view and can allow the whole nebula to be seen. 
C)  binoculars because telescopes tend to wash out the beautiful colors of the nebulae. 
D)  the naked eye because these objects are easily seen when one knows where to look.

How large will the Sun be as a red giant?

At what point in its evolution does a protostar stop shrinking and stabilize into a star?

In star-forming regions in interstellar space, which molecule is the easiest to detect?

The process of evolution of stars in the universe has been interpreted by

Which of these stars could be classified as a Population II star?

Which of these objects is NOT an abundant physical component of the interstellar medium?

Which of these properties is a known characteristic of a T Tauri star?

Which of these objects are NOT very young stars or prestellar objects?

Which one (if any) of these objects is a star in the sense that its main source of energy is nuclear fusion of normal hydrogen?

To detect most interstellar material requires

What is the minimum mass necessary in a protostar for it to begin hydrogen fusion reactions and become a main-sequence star?

What determines whether a particular region of an interstellar cloud can collapse and form a star?

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

The total lifespan of the Sun is believed to be

What is believed to prevent stars from being larger than a few hundred solar masses?

Which of these events does NOT happen in a star in the course of its evolution?

How many stars are there in a large globular cluster?

When core helium burning begins in the Sun, the Sun will have a size (radius) roughly equal to

Which of these conditions does NOT characterize the transition from a pre-main-sequence star to a main-sequence star?

For an amateur astronomer to observe some of the more visible nebulae, it is suggested that the instrument to be used is

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Exam 13: The Lives of Stars From Birth Through Middle Age

How large will the Sun be as a red giant?

At what point in its evolution does a protostar stop shrinking and stabilize into a star?

In star-forming regions in interstellar space, which molecule is the easiest to detect?

The process of evolution of stars in the universe has been interpreted by

Which of these stars could be classified as a Population II star?

Which of these objects is NOT an abundant physical component of the interstellar medium?

Which of these properties is a known characteristic of a T Tauri star?

Which of these objects are NOT very young stars or prestellar objects?

Which one (if any) of these objects is a star in the sense that its main source of energy is nuclear fusion of normal hydrogen?

To detect most interstellar material requires

What is the minimum mass necessary in a protostar for it to begin hydrogen fusion reactions and become a main-sequence star?

What determines whether a particular region of an interstellar cloud can collapse and form a star?

What is happening in a star that is on the main sequence on the Hertzsprung-Russell diagram?

The total lifespan of the Sun is believed to be

What is believed to prevent stars from being larger than a few hundred solar masses?

Which of these events does NOT happen in a star in the course of its evolution?

How many stars are there in a large globular cluster?

When core helium burning begins in the Sun, the Sun will have a size (radius) roughly equal to

Which of these conditions does NOT characterize the transition from a pre-main-sequence star to a main-sequence star?

For an amateur astronomer to observe some of the more visible nebulae, it is suggested that the instrument to be used is

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters