Question 1

The production of large numbers of neutrons in nuclear reactions at the core of a massive star helps rob the core of energy and speeds its eventual collapse.

Accepted Answer

A) True 
 B)False  True

Question 2

The nuclear reaction that produces most of the energy for massive main-sequence stars is called the CNO cycle.

Accepted Answer

A) True 
 B)False  True

Question 3

Neutron stars have masses that range from:

Accepted Answer

A)  3.5 M $\odot$  to 25 M $\odot$ 
B)  1.2 M $\odot$  to 30 M $\odot$ 
C)  2.5 M $\odot$  to 10 M $\odot$ 
D)  1.4 M $\odot$ to 3 M $\odot$ 
E)  0.1M $\odot$ to 1.4 M $\odot$ 
A)  3.5 M $\odot$  to 25 M $\odot$ 
B)  1.2 M $\odot$  to 30 M $\odot$ 
C)  2.5 M $\odot$  to 10 M $\odot$ 
D)  1.4 M $\odot$ to 3 M $\odot$ 
E)  0.1M $\odot$ to 1.4 M $\odot$ D

Question 4

Iron has 26 protons in its nucleus, and gold has 79 protons. Where did all the gold on the Earth come from?

Accepted Answer

A)  nucleosynthesis on the surfaces of neutron stars 
B)  nucleosynthesis that took place in supernova explosions 
C)  nucleosynthesis in the cores of low-mass stars 
D)  nucleosynthesis in the cores of massive stars 
E)  nucleosynthesis in red giant and horizontal-branch stars 
A)  nucleosynthesis on the surfaces of neutron stars 
B)  nucleosynthesis that took place in supernova explosions 
C)  nucleosynthesis in the cores of low-mass stars 
D)  nucleosynthesis in the cores of massive stars 
E)  nucleosynthesis in red giant and horizontal-branch stars

Question 5

The Crab Nebula is an important test of our ideas about supernova explosions because:

Accepted Answer

A)  people saw the supernova and later astronomers found a pulsar inside the nebula 
B)  the system contains an X-ray binary 
C)  the nebula is expanding slowly, as expected from mass loss rates in massive stars 
D)  the original star must have been like the Sun before it exploded 
E)  astronomers observed the merger of the two stars 
A)  people saw the supernova and later astronomers found a pulsar inside the nebula 
B)  the system contains an X-ray binary 
C)  the nebula is expanding slowly, as expected from mass loss rates in massive stars 
D)  the original star must have been like the Sun before it exploded 
E)  astronomers observed the merger of the two stars

Question 6

Every pulsar is a neutron star, but not every neutron star is a pulsar.

Accepted Answer

A) True 
 B)False

Question 7

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

Accepted Answer

Cepheids are supergiant, massive stars,

Question 8

The CNO cycle is the dominant mechanism for hydrogen fusion only in high-mass main-sequence stars because of the greater __________ their cores.

Accepted Answer

A)  concentration of heavy elements like carbon in 
B)  turbulence in 
C)  abundance of hydrogen in 
D)  temperature of 
E)  rotation speed of 
A)  concentration of heavy elements like carbon in 
B)  turbulence in 
C)  abundance of hydrogen in 
D)  temperature of 
E)  rotation speed of

Question 9

Explain the effect of core convection on the main-sequence lifetime of massive main-sequence stars and contrast this to the situation in low-mass stars.

Accepted Answer

In massive stars, convection mixes the h

Question 10

The evolutionary differences between high- and low-mass stars can be attributed to differences in the amount of mass each star possesses.

Accepted Answer

A) True 
 B)False

Question 11

When the first pulsar was discovered, scientists thought it might be a signal from a distant extraterrestrial civilization. However, this idea was quickly discarded because:

Accepted Answer

A)  it was realized the signals were interference from cars and trucks passing by the radio observatory 
B)  the government made the scientists hide their original finding 
C)  they realized that Cepheid variables could produce the detected radio signals 
D)  more pulsars were discovered, which meant that these were natural phenomena 
E)  the technology required to create pulsed signals is beyond the power of any civilization 
A)  it was realized the signals were interference from cars and trucks passing by the radio observatory 
B)  the government made the scientists hide their original finding 
C)  they realized that Cepheid variables could produce the detected radio signals 
D)  more pulsars were discovered, which meant that these were natural phenomena 
E)  the technology required to create pulsed signals is beyond the power of any civilization

Question 12

A neutron star in a mass-transfer binary system is called:

Accepted Answer

A)  a quasar 
B)  a double star 
C)  an X-ray binary 
D)  a Cepheid variable 
E)  a white dwarf star 
A)  a quasar 
B)  a double star 
C)  an X-ray binary 
D)  a Cepheid variable 
E)  a white dwarf star

Question 13

Type I and Type II supernovae can be distinguished by what combination of observations?

Accepted Answer

A)  light curves and the detection of energetic cosmic rays 
B)  light curves and the detection of neutrons 
C)  light curves and the detection of radio pulses 
D)  spectra and light curves 
E)  spectra and X-ray emission 
A)  light curves and the detection of energetic cosmic rays 
B)  light curves and the detection of neutrons 
C)  light curves and the detection of radio pulses 
D)  spectra and light curves 
E)  spectra and X-ray emission

Question 14

What is the meaning of nuclear binding energy?

Accepted Answer

The binding energy of a nucleus is the e

Question 15

High-mass stars differ from low-mass stars in that they burn helium to carbon when on the main sequence.

Accepted Answer

A) True 
 B)False

Question 16

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 
E)  composition 
A)  age 
B)  rotation period 
C)  distance 
D)  mass 
E)  composition

Question 17

Each stage of nuclear burning in 25 M $\odot$  star is __________ in duration than in a star of 15 M $\odot$ .

Accepted Answer

A)  much shorter 
B)  a little shorter 
C)  equally long 
D)  a little longer 
E)  much longer 
A)  much shorter 
B)  a little shorter 
C)  equally long 
D)  a little longer 
E)  much longer

Question 18

Where did the iron in your blood come from?

Accepted Answer

A)  nucleosynthesis on the surfaces of neutron stars 
B)  nucleosynthesis that took place in supernova explosions 
C)  nucleosynthesis in the cores of low-mass stars 
D)  nucleosynthesis in the cores of massive stars 
E)  nucleosynthesis in red giant and horizontal-branch stars 
A)  nucleosynthesis on the surfaces of neutron stars 
B)  nucleosynthesis that took place in supernova explosions 
C)  nucleosynthesis in the cores of low-mass stars 
D)  nucleosynthesis in the cores of massive stars 
E)  nucleosynthesis in red giant and horizontal-branch stars

Question 19

Although a Type II supernova shines with a luminosity of 100 billion L $\odot$  in light, most of the energy in the explosion is emitted in another way. What is it, and how much more energy does it carry compared to the light?

Accepted Answer

The majority of the energy released in a

Question 20

Cepheid variable stars are important because we can use them to determine the distance to any stellar group that contains some of these stars.

Accepted Answer

A) True 
 B)False

Exam 17: Evolution of High-Mass Stars

The production of large numbers of neutrons in nuclear reactions at the core of a massive star helps rob the core of energy and speeds its eventual collapse.

The nuclear reaction that produces most of the energy for massive main-sequence stars is called the CNO cycle.

Neutron stars have masses that range from:

Iron has 26 protons in its nucleus, and gold has 79 protons. Where did all the gold on the Earth come from?

The Crab Nebula is an important test of our ideas about supernova explosions because:

Every pulsar is a neutron star, but not every neutron star is a pulsar.

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

The CNO cycle is the dominant mechanism for hydrogen fusion only in high-mass main-sequence stars because of the greater __________ their cores.

Explain the effect of core convection on the main-sequence lifetime of massive main-sequence stars and contrast this to the situation in low-mass stars.

The evolutionary differences between high- and low-mass stars can be attributed to differences in the amount of mass each star possesses.

When the first pulsar was discovered, scientists thought it might be a signal from a distant extraterrestrial civilization. However, this idea was quickly discarded because:

A neutron star in a mass-transfer binary system is called:

Type I and Type II supernovae can be distinguished by what combination of observations?

What is the meaning of nuclear binding energy?

High-mass stars differ from low-mass stars in that they burn helium to carbon when on the main sequence.

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

Each stage of nuclear burning in 25 M ⊙\odot⊙ star is __________ in duration than in a star of 15 M ⊙\odot⊙ .

Where did the iron in your blood come from?

Although a Type II supernova shines with a luminosity of 100 billion L ⊙\odot⊙ in light, most of the energy in the explosion is emitted in another way. What is it, and how much more energy does it carry compared to the light?

Cepheid variable stars are important because we can use them to determine the distance to any stellar group that contains some of these stars.

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

Each stage of nuclear burning in 25 M _$\odot$ star is __________ in duration than in a star of 15 M _$\odot$ .

Although a Type II supernova shines with a luminosity of 100 billion L _$\odot$ in light, most of the energy in the explosion is emitted in another way. What is it, and how much more energy does it carry compared to the light?