Question 1

The structure of the deep interior of a low-mass star near the end of its life is a(n)

Accepted Answer

A)  carbon-oxygen core, a shell around the core where helium nuclei are undergoing fusion, and a surrounding shell of hydrogen. 
B)  inactive hydrogen core and a helium shell undergoing nuclear fusion surrounded by a carbon-oxygen shell. 
C)  turbulent mixture of hydrogen, helium, carbon, and oxygen in which only helium continues to undergo nuclear fusion. 
D)  helium core surrounded by a thin hydrogen shell undergoing nuclear fusion with very small concentrations of heavier nuclei. 
A)  carbon-oxygen core, a shell around the core where helium nuclei are undergoing fusion, and a surrounding shell of hydrogen. 
B)  inactive hydrogen core and a helium shell undergoing nuclear fusion surrounded by a carbon-oxygen shell. 
C)  turbulent mixture of hydrogen, helium, carbon, and oxygen in which only helium continues to undergo nuclear fusion. 
D)  helium core surrounded by a thin hydrogen shell undergoing nuclear fusion with very small concentrations of heavier nuclei. A

Question 2

Many possible explanations were offered when pulsars were first discovered. Which one of these proved to be correct?

Accepted Answer

A)  alien civilizations 
B)  expansion and contraction 
C)  small rotating object 
D)  large rotating object 
A)  alien civilizations 
B)  expansion and contraction 
C)  small rotating object 
D)  large rotating object C

Question 3

The Crab Nebula is a nearby example of what type of physical phenomenon?

Accepted Answer

A)  planetary nebula, a shell of gas leaving an old star 
B)  remnant of a supernova explosion 
C)  spiral galaxy, a collection of 100 billion stars 
D)  gas and dust cloud, the formation region for new stars 
A)  planetary nebula, a shell of gas leaving an old star 
B)  remnant of a supernova explosion 
C)  spiral galaxy, a collection of 100 billion stars 
D)  gas and dust cloud, the formation region for new stars B

Question 4

The generation of magnetic fields requires both a rapid rotation and a fluid interior for the flow of currents of charged particles. But neutrons are electrically neutral, so how can a neutron star generate a magnetic field?

Accepted Answer

A)  Neutrons in neutron degeneracy in a neutron star acquire an electric charge. 
B)  Because the neutrons in a neutron star flow through a superconducting medium, they do not need to carry an electric charge in order to constitute a current. 
C)  The enormous amounts of friction experienced by degenerate neutrons cause electric charges to build up on their surfaces, like static electricity. 
D)  Neutron stars actually contain some protons and electrons, which carry the electric currents. 
A)  Neutrons in neutron degeneracy in a neutron star acquire an electric charge. 
B)  Because the neutrons in a neutron star flow through a superconducting medium, they do not need to carry an electric charge in order to constitute a current. 
C)  The enormous amounts of friction experienced by degenerate neutrons cause electric charges to build up on their surfaces, like static electricity. 
D)  Neutron stars actually contain some protons and electrons, which carry the electric currents.

Question 5

From the start of collapse to the attainment of nuclear density, the process of core collapse at the end of the life of a massive star takes about

Accepted Answer

A)  1/2000 second. 
B)  8 minutes. 
C)  a few hours. 
D)  1 second. 
A)  1/2000 second. 
B)  8 minutes. 
C)  a few hours. 
D)  1 second.

Question 6

Just before it exploded, the star that became supernova 1987A was a(n)

Accepted Answer

A)  pulsar. 
B)  white dwarf. 
C)  M2 supergiant. 
D)  B3 supergiant. 
A)  pulsar. 
B)  white dwarf. 
C)  M2 supergiant. 
D)  B3 supergiant.

Question 7

What is it that keeps a white dwarf star from collapsing inward on itself?

Accepted Answer

A)  electron degeneracy, or "quantum crowding" 
B)  physical size of the neutrons of which this star is composed 
C)  convection currents or updrafts from the nuclear furnace 
D)  normal gas pressure 
A)  electron degeneracy, or "quantum crowding" 
B)  physical size of the neutrons of which this star is composed 
C)  convection currents or updrafts from the nuclear furnace 
D)  normal gas pressure

Question 8

A Type II supernova is the

Accepted Answer

A)  collapse of a blue supergiant star to form a black hole. 
B)  explosion of a white dwarf in a binary star system after mass has been transferred onto it from its companion. 
C)  explosion of a red giant star as a result of a helium flash in the core. 
D)  explosion of a massive star after silicon fusion has produced a core of iron nuclei. 
A)  collapse of a blue supergiant star to form a black hole. 
B)  explosion of a white dwarf in a binary star system after mass has been transferred onto it from its companion. 
C)  explosion of a red giant star as a result of a helium flash in the core. 
D)  explosion of a massive star after silicon fusion has produced a core of iron nuclei.

Question 9

The main source of moderate-energy cosmic rays, the high-energy atomic nuclei that strike Earth's atmosphere from interstellar space, is believed to be

Accepted Answer

A)  rotating, magnetized neutron stars. 
B)  matter from accretion disks surrounding neutron stars and black holes. 
C)  acceleration of nuclei by neutrinos during supernova explosions. 
D)  supernova debris colliding with interstellar material. 
A)  rotating, magnetized neutron stars. 
B)  matter from accretion disks surrounding neutron stars and black holes. 
C)  acceleration of nuclei by neutrinos during supernova explosions. 
D)  supernova debris colliding with interstellar material.

Question 10

The Crab Nebula is

Accepted Answer

A)  a supernova remnant. 
B)  a planetary nebula surrounding a hot star. 
C)  a cool, gaseous nebula in which stars are forming. 
D)  the active nucleus of a nearby spiral galaxy. 
A)  a supernova remnant. 
B)  a planetary nebula surrounding a hot star. 
C)  a cool, gaseous nebula in which stars are forming. 
D)  the active nucleus of a nearby spiral galaxy.

Question 11

What is a supernova impostor?

Accepted Answer

A)  a massive star that experiences recurrent brightening to levels comparable to a supernova explosion 
B)  an exceptionally strong nova, or runaway thermonuclear explosion on the surface of a white dwarf 
C)  the collision of two neutron stars 
D)  a gamma-ray burst with no afterglow 
A)  a massive star that experiences recurrent brightening to levels comparable to a supernova explosion 
B)  an exceptionally strong nova, or runaway thermonuclear explosion on the surface of a white dwarf 
C)  the collision of two neutron stars 
D)  a gamma-ray burst with no afterglow

Question 12

In which order do the stages of core nuclear fusion occur in the evolution of a massive star?

Accepted Answer

A)  carbon, helium, oxygen, neon 
B)  helium, carbon, neon, oxygen 
C)  helium, oxygen, carbon, neon 
D)  helium, carbon, oxygen, neon 
A)  carbon, helium, oxygen, neon 
B)  helium, carbon, neon, oxygen 
C)  helium, oxygen, carbon, neon 
D)  helium, carbon, oxygen, neon

Question 13

Young white dwarfs radiate MOST strongly in the ultraviolet, with a peak wavelength of perhaps 300 nm. What would be the surface temperature of a white dwarf?

Accepted Answer

A)  12,600 K 
B)  9700 K 
C)  7800 K 
D)  3500 K 
A)  12,600 K 
B)  9700 K 
C)  7800 K 
D)  3500 K

Question 14

What is a pulsar?

Accepted Answer

A)  very hot material orbiting a black hole 
B)  Cepheid variable star with a period of a few days 
C)  pulsating white dwarf star, fluctuating rapidly in brightness 
D)  rapidly rotating neutron star, producing beams of radio energy and occasionally of X-rays and visible light 
A)  very hot material orbiting a black hole 
B)  Cepheid variable star with a period of a few days 
C)  pulsating white dwarf star, fluctuating rapidly in brightness 
D)  rapidly rotating neutron star, producing beams of radio energy and occasionally of X-rays and visible light

Question 15

What causes a glitch in the rotation rate of a pulsar?

Accepted Answer

A)  Hot spots develop on the surface of a neutron star, and from these spots jets of material can suddenly shoot out causing a minor but abrupt chance in the rotation rate. 
B)  Because of their enormous density, the rotation rates of neutron stars are quantized and must change abruptly from one rotation rate to another. 
C)  As the star slows, its shape becomes more spherical. If its rotation rate adjusts to this suddenly, a glitch occurs. 
D)  When a pulsar occurs in a binary system, the binary companion can send clumps of material to land on its surface. This will change its rotation rate abruptly. 
A)  Hot spots develop on the surface of a neutron star, and from these spots jets of material can suddenly shoot out causing a minor but abrupt chance in the rotation rate. 
B)  Because of their enormous density, the rotation rates of neutron stars are quantized and must change abruptly from one rotation rate to another. 
C)  As the star slows, its shape becomes more spherical. If its rotation rate adjusts to this suddenly, a glitch occurs. 
D)  When a pulsar occurs in a binary system, the binary companion can send clumps of material to land on its surface. This will change its rotation rate abruptly.

Question 16

The Scorpius-Centaurus OB association is predicted to have produced a supernova about 2 million years ago. What led to this prediction?

Accepted Answer

A)  A supernova remnant with the appropriate location and age was found. 
B)  O and B stars are massive stars, many of them over 25 solar masses, and they would create a supernova. 
C)  In a close association, collisions between stars are expected, and collisions would raise the mass to the supernova range. 
D)  Shock waves from the direction of Scorpius-Centaurus still pass by Earth at frequent intervals. 
A)  A supernova remnant with the appropriate location and age was found. 
B)  O and B stars are massive stars, many of them over 25 solar masses, and they would create a supernova. 
C)  In a close association, collisions between stars are expected, and collisions would raise the mass to the supernova range. 
D)  Shock waves from the direction of Scorpius-Centaurus still pass by Earth at frequent intervals.

Question 17

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses will end up as pure helium?

Accepted Answer

A)  less than 0.4 MSun 
B)  0.4 MSun to 2 MSun only 
C)  2 MSun to 8 MSun only 
D)  all stars 0.4 MSun to 8 MSun 
A)  less than 0.4 MSun 
B)  0.4 MSun to 2 MSun only 
C)  2 MSun to 8 MSun only 
D)  all stars 0.4 MSun to 8 MSun

Question 18

At which phase of its evolutionary life is a white dwarf star?

Accepted Answer

A)  post-supernova phase, the central remnant of the explosion 
B)  just at main-sequence, or hydrogen-fusion, phase 
C)  very late for small-mass stars, in the dying phase 
D)  in its early phases, soon after formation 
A)  post-supernova phase, the central remnant of the explosion 
B)  just at main-sequence, or hydrogen-fusion, phase 
C)  very late for small-mass stars, in the dying phase 
D)  in its early phases, soon after formation

Question 19

Based on observations of supernova explosions in distant galaxies, it is predicted that 5 supernovae per century should occur in the Milky Way Galaxy, but roughly 1 supernova every 300 years has been observed from Earth. Which statement BEST explains this?

Accepted Answer

A)  The majority of supernovae produce no visible light, only radio and X-ray radiation, which have been observable from Earth for only the past three decades. 
B)  Most supernovae occur in the galactic plane, where interstellar dust has hidden them from the view from Earth. 
C)  Most supernovae occur in the Milky Way and can be seen only from the southern hemisphere, where there have been very few observers until recently. 
D)  The majority of stars in the Galaxy are old, well beyond the supernova stage of evolution. 
A)  The majority of supernovae produce no visible light, only radio and X-ray radiation, which have been observable from Earth for only the past three decades. 
B)  Most supernovae occur in the galactic plane, where interstellar dust has hidden them from the view from Earth. 
C)  Most supernovae occur in the Milky Way and can be seen only from the southern hemisphere, where there have been very few observers until recently. 
D)  The majority of stars in the Galaxy are old, well beyond the supernova stage of evolution.

Question 20

The nuclear process in which helium fusion occurs in the deep interiors of red giant stars produces

Accepted Answer

A)  iron nuclei. 
B)  carbon and oxygen nuclei. 
C)  hydrogen nuclei by the splitting of helium nuclei. 
D)  pure energy from the nuclear mass. 
A)  iron nuclei. 
B)  carbon and oxygen nuclei. 
C)  hydrogen nuclei by the splitting of helium nuclei. 
D)  pure energy from the nuclear mass.

The structure of the deep interior of a low-mass star near the end of its life is a(n)

Many possible explanations were offered when pulsars were first discovered. Which one of these proved to be correct?

The Crab Nebula is a nearby example of what type of physical phenomenon?

The generation of magnetic fields requires both a rapid rotation and a fluid interior for the flow of currents of charged particles. But neutrons are electrically neutral, so how can a neutron star generate a magnetic field?

From the start of collapse to the attainment of nuclear density, the process of core collapse at the end of the life of a massive star takes about

Just before it exploded, the star that became supernova 1987A was a(n)

What is it that keeps a white dwarf star from collapsing inward on itself?

A Type II supernova is the

The main source of moderate-energy cosmic rays, the high-energy atomic nuclei that strike Earth's atmosphere from interstellar space, is believed to be

The Crab Nebula is

What is a supernova impostor?

In which order do the stages of core nuclear fusion occur in the evolution of a massive star?

Young white dwarfs radiate MOST strongly in the ultraviolet, with a peak wavelength of perhaps 300 nm. What would be the surface temperature of a white dwarf?

What is a pulsar?

What causes a glitch in the rotation rate of a pulsar?

The Scorpius-Centaurus OB association is predicted to have produced a supernova about 2 million years ago. What led to this prediction?

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses will end up as pure helium?

At which phase of its evolutionary life is a white dwarf star?

Based on observations of supernova explosions in distant galaxies, it is predicted that 5 supernovae per century should occur in the Milky Way Galaxy, but roughly 1 supernova every 300 years has been observed from Earth. Which statement BEST explains this?

The nuclear process in which helium fusion occurs in the deep interiors of red giant stars produces

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 Lives of Stars From Birth Through Middle Age

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

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Exam 14: The Death of Stars

The structure of the deep interior of a low-mass star near the end of its life is a(n)

Many possible explanations were offered when pulsars were first discovered. Which one of these proved to be correct?

The Crab Nebula is a nearby example of what type of physical phenomenon?

The generation of magnetic fields requires both a rapid rotation and a fluid interior for the flow of currents of charged particles. But neutrons are electrically neutral, so how can a neutron star generate a magnetic field?

From the start of collapse to the attainment of nuclear density, the process of core collapse at the end of the life of a massive star takes about

Just before it exploded, the star that became supernova 1987A was a(n)

What is it that keeps a white dwarf star from collapsing inward on itself?

A Type II supernova is the

The main source of moderate-energy cosmic rays, the high-energy atomic nuclei that strike Earth's atmosphere from interstellar space, is believed to be

The Crab Nebula is

What is a supernova impostor?

In which order do the stages of core nuclear fusion occur in the evolution of a massive star?

Young white dwarfs radiate MOST strongly in the ultraviolet, with a peak wavelength of perhaps 300 nm. What would be the surface temperature of a white dwarf?

What is a pulsar?

What causes a glitch in the rotation rate of a pulsar?

The Scorpius-Centaurus OB association is predicted to have produced a supernova about 2 million years ago. What led to this prediction?

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses will end up as pure helium?

At which phase of its evolutionary life is a white dwarf star?

Based on observations of supernova explosions in distant galaxies, it is predicted that 5 supernovae per century should occur in the Milky Way Galaxy, but roughly 1 supernova every 300 years has been observed from Earth. Which statement BEST explains this?

The nuclear process in which helium fusion occurs in the deep interiors of red giant stars produces

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 Lives of Stars From Birth Through Middle Age

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters