Question 1

What is a T Tauri star?

Accepted Answer

A)  a young G, K, or M star that is ejecting gas 
B)  a giant or supergiant star that varies regularly in brightness 
C)  a giant or supergiant star that varies randomly in brightness 
D)  a massing O or B star that ionizes hydrogen in interstellar space 
A)  a young G, K, or M star that is ejecting gas 
B)  a giant or supergiant star that varies regularly in brightness 
C)  a giant or supergiant star that varies randomly in brightness 
D)  a massing O or B star that ionizes hydrogen in interstellar space

Question 2

What is the MOST abundant element in the universe?

Accepted Answer

A)  carbon 
B)  helium 
C)  oxygen 
D)  hydrogen 
A)  carbon 
B)  helium 
C)  oxygen 
D)  hydrogen

Question 3

In a Cepheid variable,what happens to make the temperature decrease?

Accepted Answer

A)  Massive solar flares release great amounts of energy, after which the star goes through a partial collapse. 
B)  Hydrogen fusion in the shell begins to shut down because it is running low on fuel. 
C)  A periodic eruption of sunspots blocks the radiation from below. 
D)  The ionized helium layer expands and cools. 
A)  Massive solar flares release great amounts of energy, after which the star goes through a partial collapse. 
B)  Hydrogen fusion in the shell begins to shut down because it is running low on fuel. 
C)  A periodic eruption of sunspots blocks the radiation from below. 
D)  The ionized helium layer expands and cools.

Question 4

Cepheid variables pulsate because they contain a layer that alternately blocks photons while heating and then becomes transparent to photons as it expands.What substance composes this layer?

Accepted Answer

A)  hydrogen 
B)  deuterium 
C)  ionized helium 
D)  twice-ionized carbon 
A)  hydrogen 
B)  deuterium 
C)  ionized helium 
D)  twice-ionized carbon

Question 5

A protostar eventually becomes a pre-main-sequence star.Each of the following statements characterizes this transition EXCEPT ONE.Which is the exception?

Accepted Answer

A)  In the pre-main-sequence star, the rate of collapse slows. 
B)  In the pre-main-sequence star, the core temperature is greater. 
C)  The pre-main-sequence star is larger. 
D)  The strong stellar winds and irregular shapes associated with protostars continue through the transition to the pre-main-sequence star. 
A)  In the pre-main-sequence star, the rate of collapse slows. 
B)  In the pre-main-sequence star, the core temperature is greater. 
C)  The pre-main-sequence star is larger. 
D)  The strong stellar winds and irregular shapes associated with protostars continue through the transition to the pre-main-sequence star.

Question 6

The next stage in a star's life after the main-sequence phase is:

Accepted Answer

A)  the red giant phase. 
B)  the horizontal-branch phase. 
C)  a protostar. 
D)  death (i.e., either a supernova or a white dwarf). 
A)  the red giant phase. 
B)  the horizontal-branch phase. 
C)  a protostar. 
D)  death (i.e., either a supernova or a white dwarf).

Question 7

The "helium flash" occurs in a 2-solar-mass star when:

Accepted Answer

A)  the core heats up from helium fusion and the gas does not expand to cool down and stabilize the temperature because the gas properties are controlled by degenerate electrons. 
B)  convection within the star carries helium to the surface, where it shows its own characteristic spectrum for the first time. 
C)  hydrogen fusion ceases abruptly, leaving only the fusion of helium to generate energy. 
D)  the core temperature becomes sufficiently high for helium fusion for the first time. 
A)  the core heats up from helium fusion and the gas does not expand to cool down and stabilize the temperature because the gas properties are controlled by degenerate electrons. 
B)  convection within the star carries helium to the surface, where it shows its own characteristic spectrum for the first time. 
C)  hydrogen fusion ceases abruptly, leaving only the fusion of helium to generate energy. 
D)  the core temperature becomes sufficiently high for helium fusion for the first time.

Question 8

In a Cepheid variable,what happens to make its temperature rise?

Accepted Answer

A)  A layer of ionized helium absorbs photons. 
B)  The fusion reaction switches from hydrogen fusion to helium fusion. 
C)  The hydrogen fusion in the shell increases as it receives a periodic burst of convection current-carried fuel. 
D)  The electron degeneracy in the core refuses to allow the core to expand in response to energy generation. 
A)  A layer of ionized helium absorbs photons. 
B)  The fusion reaction switches from hydrogen fusion to helium fusion. 
C)  The hydrogen fusion in the shell increases as it receives a periodic burst of convection current-carried fuel. 
D)  The electron degeneracy in the core refuses to allow the core to expand in response to energy generation.

Question 9

Open clusters are not:

Accepted Answer

A)  gravitationally bound. 
B)  the result of star formation within a single giant molecular cloud. 
C)  associated with solo stars like our Sun. 
D)  known to contain more than about a hundred stars. 
A)  gravitationally bound. 
B)  the result of star formation within a single giant molecular cloud. 
C)  associated with solo stars like our Sun. 
D)  known to contain more than about a hundred stars.

Question 10

Accretion of matter in an interstellar cloud leads to:

Accepted Answer

A)  a supernova explosion since accretion is a nuclear process. 
B)  the explosion of this matter when it is attracted to and falls onto the surfaces of stars. 
C)  the formation of molecules from atomic gases. 
D)  a protostar. 
A)  a supernova explosion since accretion is a nuclear process. 
B)  the explosion of this matter when it is attracted to and falls onto the surfaces of stars. 
C)  the formation of molecules from atomic gases. 
D)  a protostar.

Question 11

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)  the 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)  the amount of mass in the cloud since mass determines the strength of gravity 
A)  temperature since higher temperatures act to prevent collapse 
B)  the 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)  the amount of mass in the cloud since mass determines the strength of gravity

Question 12

When looking for molecular hydrogen,astronomers actually look for:

Accepted Answer

A)  atomic hydrogen. 
B)  carbon monoxide. 
C)  carbon dioxide. 
D)  buckminsterfullerene (buckeyballs). 
A)  atomic hydrogen. 
B)  carbon monoxide. 
C)  carbon dioxide. 
D)  buckminsterfullerene (buckeyballs).

Question 13

When a variable star periodically changes its luminosity,each of the following also changes periodically EXCEPT ONE.Which is the exception?

Accepted Answer

A)  temperature 
B)  radial surface speed 
C)  size 
D)  rotation rate 
A)  temperature 
B)  radial surface speed 
C)  size 
D)  rotation rate

Question 14

When attempting to observe a protostar,which region of the spectrum do we usually use?

Accepted Answer

A)  visible because protostars do emit visible light 
B)  infrared because protostars emit only infrared light 
C)  infrared because these longer wavelengths can penetrate the dust surrounding the protostar 
D)  ultraviolet because their higher energy photons can penetrate the dust surrounding the protostar 
A)  visible because protostars do emit visible light 
B)  infrared because protostars emit only infrared light 
C)  infrared because these longer wavelengths can penetrate the dust surrounding the protostar 
D)  ultraviolet because their higher energy photons can penetrate the dust surrounding the protostar

Question 15

What is a Roche lobe?

Accepted Answer

A)  an imaginary boundary around each star in a close binary system encompassing the mass gravitationally bound to that star 
B)  an imaginary boundary around each star in a close binary system that marks the limit outside which planets cannot form 
C)  an imaginary boundary around each star in a close binary system that marks the limit inside which planets cannot form because they would be torn apart by the star's gravity 
D)  an imaginary boundary around each star in a close binary system that marks the limit of each star's gravitational pull and within which the stars will have no effect on each other 
A)  an imaginary boundary around each star in a close binary system encompassing the mass gravitationally bound to that star 
B)  an imaginary boundary around each star in a close binary system that marks the limit outside which planets cannot form 
C)  an imaginary boundary around each star in a close binary system that marks the limit inside which planets cannot form because they would be torn apart by the star's gravity 
D)  an imaginary boundary around each star in a close binary system that marks the limit of each star's gravitational pull and within which the stars will have no effect on each other

Question 16

The helium flash results from the:

Accepted Answer

A)  sudden release of energy in strong magnetic fields near a sunspot. 
B)  electron degeneracy or quantum crowding in the core of a low-mass red giant star. 
C)  sudden onset of nuclear reactions at the end of the protostar. 
D)  high temperature in the helium core of a blue (spectral class O or 
B)  supergiant star. 
A)  sudden release of energy in strong magnetic fields near a sunspot. 
B)  electron degeneracy or quantum crowding in the core of a low-mass red giant star. 
C)  sudden onset of nuclear reactions at the end of the protostar. 
D)  high temperature in the helium core of a blue (spectral class O or 
B)  supergiant star.

Question 17

Because all the stars in a cluster begin forming at the same time,the stars arrive on the main sequence at:

Accepted Answer

A)  the same time. 
B)  different times, more massive stars arrive first. 
C)  different times, less massive stars arrive first. 
D)  different times, later spectral types (G, K, M) arrive first. 
A)  the same time. 
B)  different times, more massive stars arrive first. 
C)  different times, less massive stars arrive first. 
D)  different times, later spectral types (G, K, M) arrive first.

Question 18

What process is involved in the helium flash?

Accepted Answer

A)  An increase in temperature causes an increase in the nuclear reaction rate but has no effect on pressure. 
B)  An increase in the pressure causes a decrease in the temperature and the nuclear reaction rate. 
C)  An increase in temperature causes an increase in the pressure with no increase in the nuclear reaction rate. 
D)  An increase in the nuclear reaction rate causes an increase in the temperature and the pressure. 
A)  An increase in temperature causes an increase in the nuclear reaction rate but has no effect on pressure. 
B)  An increase in the pressure causes a decrease in the temperature and the nuclear reaction rate. 
C)  An increase in temperature causes an increase in the pressure with no increase in the nuclear reaction rate. 
D)  An increase in the nuclear reaction rate causes an increase in the temperature and the pressure.

Question 19

Will the Sun undergo a helium flash?

Accepted Answer

A)  Yes. 
B)  No. Only stars more massive than the Sun experience a helium flash. 
C)  No. Only stars less massive than the Sun experience a helium flash. 
D)  No. The Sun is now in the correct mass range to experience a helium flash, but by the time it ends its life on the main sequence it will have lost enough mass that it will no longer be in the correct range. 
A)  Yes. 
B)  No. Only stars more massive than the Sun experience a helium flash. 
C)  No. Only stars less massive than the Sun experience a helium flash. 
D)  No. The Sun is now in the correct mass range to experience a helium flash, but by the time it ends its life on the main sequence it will have lost enough mass that it will no longer be in the correct range.

Question 20

In which part of the electromagnetic spectrum are molecules MOST easily detected?

Accepted Answer

A)  visible light 
B)  radio waves 
C)  X rays 
D)  ultraviolet light 
A)  visible light 
B)  radio waves 
C)  X rays 
D)  ultraviolet light

What is a T Tauri star?

What is the MOST abundant element in the universe?

In a Cepheid variable,what happens to make the temperature decrease?

Cepheid variables pulsate because they contain a layer that alternately blocks photons while heating and then becomes transparent to photons as it expands.What substance composes this layer?

A protostar eventually becomes a pre-main-sequence star.Each of the following statements characterizes this transition EXCEPT ONE.Which is the exception?

The next stage in a star's life after the main-sequence phase is:

The "helium flash" occurs in a 2-solar-mass star when:

In a Cepheid variable,what happens to make its temperature rise?

Open clusters are not:

Accretion of matter in an interstellar cloud leads to:

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

When looking for molecular hydrogen,astronomers actually look for:

When a variable star periodically changes its luminosity,each of the following also changes periodically EXCEPT ONE.Which is the exception?

When attempting to observe a protostar,which region of the spectrum do we usually use?

What is a Roche lobe?

The helium flash results from the:

Because all the stars in a cluster begin forming at the same time,the stars arrive on the main sequence at:

What process is involved in the helium flash?

Will the Sun undergo a helium flash?

In which part of the electromagnetic spectrum are molecules MOST easily detected?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters

Exam 11: The Lives of the Stars From Birth Through Middle Age

What is a T Tauri star?

What is the MOST abundant element in the universe?

In a Cepheid variable,what happens to make the temperature decrease?

Cepheid variables pulsate because they contain a layer that alternately blocks photons while heating and then becomes transparent to photons as it expands.What substance composes this layer?

A protostar eventually becomes a pre-main-sequence star.Each of the following statements characterizes this transition EXCEPT ONE.Which is the exception?

The next stage in a star's life after the main-sequence phase is:

The "helium flash" occurs in a 2-solar-mass star when:

In a Cepheid variable,what happens to make its temperature rise?

Open clusters are not:

Accretion of matter in an interstellar cloud leads to:

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

When looking for molecular hydrogen,astronomers actually look for:

When a variable star periodically changes its luminosity,each of the following also changes periodically EXCEPT ONE.Which is the exception?

When attempting to observe a protostar,which region of the spectrum do we usually use?

What is a Roche lobe?

The helium flash results from the:

Because all the stars in a cluster begin forming at the same time,the stars arrive on the main sequence at:

What process is involved in the helium flash?

Will the Sun undergo a helium flash?

In which part of the electromagnetic spectrum are molecules MOST easily detected?

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters