Question 1

When a shell of hydrogen accretes onto a white dwarf from a close companion, a(n)
explosion violently blows off a fraction of a solar mass.

Accepted Answer

The answer of When a shell of hydrogen accretes onto...

Question 2

Chandrasekhar's limit is 1.4 times the mass of our Sun.

Accepted Answer

A) True 
 B)False

Question 3

Once the helium flash occurs at stage 10, the star stabilizes again on the horizontal branch of the H- R diagram, but now hundreds of times as bright as on the main sequence.

Accepted Answer

A) True 
 B)False

Question 4

The helium flash requires a core temperature of K to create carbon.

Accepted Answer

The answer of The helium flash requires a core temperature...

Question 5

The main reason that stars evolved off the main sequence is because they are becoming less massive as energy is lost into space from the proton- proton cycle.

Accepted Answer

A) True 
 B)False

Question 6

A star is on the horizontal branch of the H- R diagram. Which statement is true?

Accepted Answer

A)  It is about to experience the helium flash. 
B)  It is burning both hydrogen and helium. 
C)  It is burning only helium. 
D)  The star is contracting. 
E)  The star is about to return to the main sequence. 
A)  It is about to experience the helium flash. 
B)  It is burning both hydrogen and helium. 
C)  It is burning only helium. 
D)  The star is contracting. 
E)  The star is about to return to the main sequence.

Question 7

Why do blue stragglers show up in globular clusters?

Accepted Answer

These stars appear younger tha

Question 8

A massive star can fuse only up to the element silicon in its core.

Accepted Answer

A) True 
 B)False

Question 9

The formation of carbon requires a core temperature of about 100 million K, but iron takes much higher temperatures and pressures.

Accepted Answer

A) True 
 B)False

Question 10

Why are there no black dwarfs yet, but in the future they may make up the majority of normal matter in the universe?

Accepted Answer

White dwarfs cool off slowly, so the old

Question 11

The brightest stars in a young open cluster will be

Accepted Answer

A)  Cepheid variables. 
B)  red giants. 
C)  massive blue main- sequence stars. 
D)  yellow main- sequence stars like the Sun. 
E)  T- Tauri variables. 
A)  Cepheid variables. 
B)  red giants. 
C)  massive blue main- sequence stars. 
D)  yellow main- sequence stars like the Sun. 
E)  T- Tauri variables.

Question 12

Neutrinos can move faster than c, the speed of light, as was discovered in SN1987A in 1987.

Accepted Answer

A) True 
 B)False

Question 13

When a low mass star first runs short of hydrogen in its core, it becomes brighter because

Accepted Answer

A)  its outer, cooler layers are shed, and we see the brighter central core. 
B)  the helium flash increases the size of the star immensely. 
C)  the core contracts, raising the temperature and extending the hydrogen burning shell outward. 
D)  it explodes as a nova. 
E)  helium fusion gives off more energy than does hydrogen. 
A)  its outer, cooler layers are shed, and we see the brighter central core. 
B)  the helium flash increases the size of the star immensely. 
C)  the core contracts, raising the temperature and extending the hydrogen burning shell outward. 
D)  it explodes as a nova. 
E)  helium fusion gives off more energy than does hydrogen.

Question 14

A cluster with a lot of Type O and B stars, but no bright K or M stars, is very

Accepted Answer

A)  densely packed. 
B)  faint. 
C)  poor in heavy elements. 
D)  old. 
E)  young. 
A)  densely packed. 
B)  faint. 
C)  poor in heavy elements. 
D)  old. 
E)  young.

Question 15

About 90% of the star's total life is spent on the main sequence.

Accepted Answer

A) True 
 B)False

Question 16

What would be most likely to disrupt the normal evolution of a star? Give examples of this.

Accepted Answer

If it has a close companion, mass transf

Question 17

Only low mass stars experience the temporary instability of the helium flash; high mass stars go directly into heavier element formation.

Accepted Answer

A) True 
 B)False

Question 18

The spectra of the oldest stars show the most heavy elements.

Accepted Answer

A) True 
 B)False

Question 19

You observe a low- mass helium white dwarf. What can you conclude?

Accepted Answer

A)  It is over 100 billion years old. 
B)  It was once a blue supergiant. 
C)  It will soon be a Type II supernova. 
D)  Its core is mostly carbon. 
E)  It is part of a binary star system. 
A)  It is over 100 billion years old. 
B)  It was once a blue supergiant. 
C)  It will soon be a Type II supernova. 
D)  Its core is mostly carbon. 
E)  It is part of a binary star system.

Question 20

The helium flash increases the star's luminosity.

Accepted Answer

A) True 
 B)False

When a shell of hydrogen accretes onto a white dwarf from a close companion, a(n) explosion violently blows off a fraction of a solar mass.

Chandrasekhar's limit is 1.4 times the mass of our Sun.

Once the helium flash occurs at stage 10, the star stabilizes again on the horizontal branch of the H- R diagram, but now hundreds of times as bright as on the main sequence.

The helium flash requires a core temperature of K to create carbon.

The main reason that stars evolved off the main sequence is because they are becoming less massive as energy is lost into space from the proton- proton cycle.

A star is on the horizontal branch of the H- R diagram. Which statement is true?

Why do blue stragglers show up in globular clusters?

A massive star can fuse only up to the element silicon in its core.

The formation of carbon requires a core temperature of about 100 million K, but iron takes much higher temperatures and pressures.

Why are there no black dwarfs yet, but in the future they may make up the majority of normal matter in the universe?

The brightest stars in a young open cluster will be

Neutrinos can move faster than c, the speed of light, as was discovered in SN1987A in 1987.

When a low mass star first runs short of hydrogen in its core, it becomes brighter because

A cluster with a lot of Type O and B stars, but no bright K or M stars, is very

About 90% of the star's total life is spent on the main sequence.

What would be most likely to disrupt the normal evolution of a star? Give examples of this.

Only low mass stars experience the temporary instability of the helium flash; high mass stars go directly into heavier element formation.

The spectra of the oldest stars show the most heavy elements.

You observe a low- mass helium white dwarf. What can you conclude?

The helium flash increases the star's luminosity.

Charting the Heavens: the Foundations of Astronomy

The Copernican Revolution: the Birth of Modern Science

Light and Matter: the Inner Workings of the Cosmos

Telescopes: the Tools of Astronomy

The Solar System: Interplanetary Matter and the Birth of the Planets

Earth and Its Moon: Our Cosmic Backyard

The Terrestrial Planets: a Study in Contrasts

The Jovian Planets: Giants of the Solar System

Moons, Rings, and Plutoids: Small Worlds Among Giants

The Sun: Our Parent Star

Measuring the Stars: Giants, Dwarfs, and the Main Sequence

The Interstellar Medium: Star Formation in the Milky Way

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Normal and Active Galaxies: Building Blocks of the Universe

Hubbles Law and Dark Matter: the Large-Scale Structure of the Cosmos

Cosmology: the Big Bang and the Fate of the Universe

Life in the Universe: Are We Alone

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Exam 13: Stellar Evolution: the Lives and Deaths of Stars

When a shell of hydrogen accretes onto a white dwarf from a close companion, a(n) explosion violently blows off a fraction of a solar mass.

Chandrasekhar's limit is 1.4 times the mass of our Sun.

Once the helium flash occurs at stage 10, the star stabilizes again on the horizontal branch of the H- R diagram, but now hundreds of times as bright as on the main sequence.

The helium flash requires a core temperature of K to create carbon.

The main reason that stars evolved off the main sequence is because they are becoming less massive as energy is lost into space from the proton- proton cycle.

A star is on the horizontal branch of the H- R diagram. Which statement is true?

Why do blue stragglers show up in globular clusters?

A massive star can fuse only up to the element silicon in its core.

The formation of carbon requires a core temperature of about 100 million K, but iron takes much higher temperatures and pressures.

Why are there no black dwarfs yet, but in the future they may make up the majority of normal matter in the universe?

The brightest stars in a young open cluster will be

Neutrinos can move faster than c, the speed of light, as was discovered in SN1987A in 1987.

When a low mass star first runs short of hydrogen in its core, it becomes brighter because

A cluster with a lot of Type O and B stars, but no bright K or M stars, is very

About 90% of the star's total life is spent on the main sequence.

What would be most likely to disrupt the normal evolution of a star? Give examples of this.

Only low mass stars experience the temporary instability of the helium flash; high mass stars go directly into heavier element formation.

The spectra of the oldest stars show the most heavy elements.

You observe a low- mass helium white dwarf. What can you conclude?

The helium flash increases the star's luminosity.

Charting the Heavens: the Foundations of Astronomy

The Copernican Revolution: the Birth of Modern Science

Light and Matter: the Inner Workings of the Cosmos

Telescopes: the Tools of Astronomy

The Solar System: Interplanetary Matter and the Birth of the Planets

Earth and Its Moon: Our Cosmic Backyard

The Terrestrial Planets: a Study in Contrasts

The Jovian Planets: Giants of the Solar System

Moons, Rings, and Plutoids: Small Worlds Among Giants

The Sun: Our Parent Star

Measuring the Stars: Giants, Dwarfs, and the Main Sequence

The Interstellar Medium: Star Formation in the Milky Way

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Normal and Active Galaxies: Building Blocks of the Universe

Hubbles Law and Dark Matter: the Large-Scale Structure of the Cosmos

Cosmology: the Big Bang and the Fate of the Universe

Life in the Universe: Are We Alone

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