Question 1

What is the minimum-mass main-sequence star that becomes a Type II supernova?

Accepted Answer

A)  4 M¤ 
B)  8 M¤ 
C)  12 M¤ 
D)  25 M¤ 
A)  4 M¤ 
B)  8 M¤ 
C)  12 M¤ 
D)  25 M¤

Question 2

The event horizon of a black hole is defined as:

Accepted Answer

A)  the point of maximum gravity. 
B)  the radius of the original neutron star before it became a black hole. 
C)  the point at which shock waves emanate from the strong gravitational distortion the black hole creates in the fabric of spacetime. 
D)  the radius at which the escape speed equals the speed of light. 
A)  the point of maximum gravity. 
B)  the radius of the original neutron star before it became a black hole. 
C)  the point at which shock waves emanate from the strong gravitational distortion the black hole creates in the fabric of spacetime. 
D)  the radius at which the escape speed equals the speed of light.

Question 3

We can identify only a small fraction of all the pulsars that exist in our galaxy because:

Accepted Answer

A)  gas and dust efficiently block radio photons. 
B)  few swing their beam of synchrotron emission in our direction. 
C)  most have evolved to become black holes, which emit no light. 
D)  massive stars are very rare. 
A)  gas and dust efficiently block radio photons. 
B)  few swing their beam of synchrotron emission in our direction. 
C)  most have evolved to become black holes, which emit no light. 
D)  massive stars are very rare.

Question 4

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

Accepted Answer

A)  decreasingly shorter times. 
B)  increasingly longer times. 
C)  an approximately equal amount of time. 
D)  approximately 10,000 years. 
A)  decreasingly shorter times. 
B)  increasingly longer times. 
C)  an approximately equal amount of time. 
D)  approximately 10,000 years.

Question 5

Essentially all the elements heavier than iron in our galaxy were formed:

Accepted Answer

A)  by supernovae. 
B)  during the formation of black holes. 
C)  by fusion in the cores of the most massive main-sequence stars. 
D)  during the formation of planetary nebulae. 
A)  by supernovae. 
B)  during the formation of black holes. 
C)  by fusion in the cores of the most massive main-sequence stars. 
D)  during the formation of planetary nebulae.

Question 6

Why are Cepheids important to study?

Accepted Answer

First,Cepheid variables are very bright,

Question 7

Which of the following is NOT true about Cygnus X-1?

Accepted Answer

A)  It is a binary star. 
B)  It contains a black hole. 
C)  It is a source of X-rays. 
D)  It is a neutron star. 
A)  It is a binary star. 
B)  It contains a black hole. 
C)  It is a source of X-rays. 
D)  It is a neutron star.

Question 8

When the core of a massive star collapses,a neutron star forms because:

Accepted Answer

A)  all the charged particles are ejected in the resulting explosion. 
B)  protons and electrons combine to form neutrons. 
C)  iron nuclei disintegrate into neutrons. 
D)  neutrinos escaping from the core carry away most of the electromagnetic charge. 
A)  all the charged particles are ejected in the resulting explosion. 
B)  protons and electrons combine to form neutrons. 
C)  iron nuclei disintegrate into neutrons. 
D)  neutrinos escaping from the core carry away most of the electromagnetic charge.

Question 9

Neutron stars have masses that range from:

Accepted Answer

A)  3.5 M¤ to 25 M¤. 
B)  1.2 M¤ to 30 M¤. 
C)  2.5 M¤ to 10 M¤. 
D)  1.4 M¤ to 3 M¤. 
A)  3.5 M¤ to 25 M¤. 
B)  1.2 M¤ to 30 M¤. 
C)  2.5 M¤ to 10 M¤. 
D)  1.4 M¤ to 3 M¤.

Question 10

Explain how a pulsar comes to rotate more quickly than its original high-mass star that rotated much more slowly.

Accepted Answer

Because a large amount of mass

Question 11

If you measure the average brightness and pulsation period of a Cepheid variable star,you can also determine its:

Accepted Answer

A)  age. 
B)  rotation period. 
C)  distance. 
D)  mass. 
A)  age. 
B)  rotation period. 
C)  distance. 
D)  mass.

Question 12

Where would be the best place to search for black holes?

Accepted Answer

X-ray binaries,like Cygnus X-1

Question 13

The CNO cycle in high-mass main-sequence stars burns ________ to ________in their cores.

Accepted Answer

A)  hydrogen; helium 
B)  carbon; oxygen 
C)  carbon; nitrogen 
D)  This is a trick question as the CNO cycle does not operate in high-mass main-sequence stars. 
A)  hydrogen; helium 
B)  carbon; oxygen 
C)  carbon; nitrogen 
D)  This is a trick question as the CNO cycle does not operate in high-mass main-sequence stars.

Question 14

The Type II supernova that created the Crab Nebula (image below)was seen by Chinese and Arab astronomers in the year A.D.1054.Because the star is 6,500 light-years away from us,we know the star exploded in the year:

Accepted Answer

A)  A.D. 7554. 
B)  A.D. 1054. 
C)  5446 B.C. 
D)  7554 B.C. 
A)  A.D. 7554. 
B)  A.D. 1054. 
C)  5446 B.C. 
D)  7554 B.C.

Question 15

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

Accepted Answer

A)  Most of the energy is trapped in the core, increasing the core's temperature. 
B)  All of the extra energy goes into heating the shells of fusion surrounding the core. 
C)  Most of the energy is absorbed by the outer layers of the star, increasing the star's radius but leaving its luminosity unchanged. 
D)  Most of the energy is carried out of the star by escaping neutrinos. 
A)  Most of the energy is trapped in the core, increasing the core's temperature. 
B)  All of the extra energy goes into heating the shells of fusion surrounding the core. 
C)  Most of the energy is absorbed by the outer layers of the star, increasing the star's radius but leaving its luminosity unchanged. 
D)  Most of the energy is carried out of the star by escaping neutrinos.

Question 16

Explain why Einstein's theory of general relativity predicts the existence of gravitational lensing.

Accepted Answer

Einstein's theory of general relativity

Question 17

How do Cepheid variable stars differ from RR Lyrae variable stars in their masses,luminosities,and periods?

Accepted Answer

Cepheids are supergiant,massive stars,wh

Question 18

What is the radius of the event horizon of a 10 solar mass black hole?

Accepted Answer

A)  3 km 
B)  10 km 
C)  30 km 
D)  100 km 
A)  3 km 
B)  10 km 
C)  30 km 
D)  100 km

Question 19

Galileo supposedly experimented with gravity by dropping two objects of different masses from the Leaning Tower of Pisa at the same instant and observing that they hit the ground at the same time.If Albert Einstein had done the experiment,how would his conclusion have differed from Galileo's?

Accepted Answer

Galileo would say that the acceleration

Question 20

Black holes that are stellar remnants can be found by searching for:

Accepted Answer

A)  dark regions at the centers of galaxies. 
B)  variable X-ray sources. 
C)  extremely luminous infrared objects. 
D)  objects that emit very faint radio emission. 
A)  dark regions at the centers of galaxies. 
B)  variable X-ray sources. 
C)  extremely luminous infrared objects. 
D)  objects that emit very faint radio emission.

What is the minimum-mass main-sequence star that becomes a Type II supernova?

The event horizon of a black hole is defined as:

We can identify only a small fraction of all the pulsars that exist in our galaxy because:

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

Essentially all the elements heavier than iron in our galaxy were formed:

Why are Cepheids important to study?

Which of the following is NOT true about Cygnus X-1?

When the core of a massive star collapses,a neutron star forms because:

Neutron stars have masses that range from:

Explain how a pulsar comes to rotate more quickly than its original high-mass star that rotated much more slowly.

If you measure the average brightness and pulsation period of a Cepheid variable star,you can also determine its:

Where would be the best place to search for black holes?

The CNO cycle in high-mass main-sequence stars burns to in their cores.

The Type II supernova that created the Crab Nebula (image below)was seen by Chinese and Arab astronomers in the year A.D.1054.Because the star is 6,500 light-years away from us,we know the star exploded in the year:

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

Explain why Einstein's theory of general relativity predicts the existence of gravitational lensing.

How do Cepheid variable stars differ from RR Lyrae variable stars in their masses,luminosities,and periods?

What is the radius of the event horizon of a 10 solar mass black hole?

Galileo supposedly experimented with gravity by dropping two objects of different masses from the Leaning Tower of Pisa at the same instant and observing that they hit the ground at the same time.If Albert Einstein had done the experiment,how would his conclusion have differed from Galileo's?

Black holes that are stellar remnants can be found by searching for:

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: the Sun

Evolution of Low-Mass Stars

Measuring Galaxies

Our Galaxy: the Milky Way

The Evolution of the Universe

Formation of Structure

Life in the Universe

Filters

Exam 13: Evolution of High-Mass Stars

What is the minimum-mass main-sequence star that becomes a Type II supernova?

The event horizon of a black hole is defined as:

We can identify only a small fraction of all the pulsars that exist in our galaxy because:

During the main-sequence evolution of a massive star,increasingly heavier elements are fused in the core,giving the core support for:

Essentially all the elements heavier than iron in our galaxy were formed:

Why are Cepheids important to study?

Which of the following is NOT true about Cygnus X-1?

When the core of a massive star collapses,a neutron star forms because:

Neutron stars have masses that range from:

Explain how a pulsar comes to rotate more quickly than its original high-mass star that rotated much more slowly.

If you measure the average brightness and pulsation period of a Cepheid variable star,you can also determine its:

Where would be the best place to search for black holes?

The CNO cycle in high-mass main-sequence stars burns ________ to ________in their cores.

The Type II supernova that created the Crab Nebula (image below)was seen by Chinese and Arab astronomers in the year A.D.1054.Because the star is 6,500 light-years away from us,we know the star exploded in the year:

Why does the luminosity of a high-mass star remain nearly constant as the star burns heavy elements in its core,even though it is producing millions of times more energy per second than it did on the main sequence?

Explain why Einstein's theory of general relativity predicts the existence of gravitational lensing.

How do Cepheid variable stars differ from RR Lyrae variable stars in their masses,luminosities,and periods?

What is the radius of the event horizon of a 10 solar mass black hole?

Galileo supposedly experimented with gravity by dropping two objects of different masses from the Leaning Tower of Pisa at the same instant and observing that they hit the ground at the same time.If Albert Einstein had done the experiment,how would his conclusion have differed from Galileo's?

Black holes that are stellar remnants can be found by searching for:

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: the Sun

Evolution of Low-Mass Stars

Measuring Galaxies

Our Galaxy: the Milky Way

The Evolution of the Universe

Formation of Structure

Life in the Universe

Filters

The CNO cycle in high-mass main-sequence stars burns to in their cores.