Question 1

Hypernovae are associated with

Accepted Answer

A)  binary neutron stars. 
B)  supermassive black holes. 
C)  magnetars. 
D)  explosions of extremely massive stars. 
A)  binary neutron stars. 
B)  supermassive black holes. 
C)  magnetars. 
D)  explosions of extremely massive stars.

Question 2

During its time on the asymptotic giant branch, the Sun will eventually evolve into a red supergiant star with the brightness of _____ and a diameter of _____.

Accepted Answer

A)  10,000 Suns; about Earth's orbit 
B)  the Sun; Mercury's orbit 
C)  about 1 million Suns; the whole solar system 
D)  about 10,000 Suns; 1/10 that of the Sun 
A)  10,000 Suns; about Earth's orbit 
B)  the Sun; Mercury's orbit 
C)  about 1 million Suns; the whole solar system 
D)  about 10,000 Suns; 1/10 that of the Sun

Question 3

Which of these statements about novae is FALSE?

Accepted Answer

A)  Novae occur when two white dwarfs collide. 
B)  Novae eject gas in thousands of clumps, rather than in a smooth envelope. 
C)  A white dwarf can be the origin of more than one nova. 
D)  The light curve for a typical nova shows a rapid rise followed by a gradual decline lasting a few months. 
A)  Novae occur when two white dwarfs collide. 
B)  Novae eject gas in thousands of clumps, rather than in a smooth envelope. 
C)  A white dwarf can be the origin of more than one nova. 
D)  The light curve for a typical nova shows a rapid rise followed by a gradual decline lasting a few months.

Question 4

Which of these is NOT a typical property of young neutron stars?

Accepted Answer

A)  Neutron stars rotate from 1 to 30 times per second. 
B)  Neutron stars emit relatively narrow beams of light and other radiation. 
C)  Neutron stars contain strong gravitational fields but weak magnetic fields. 
D)  Neutron stars are composed almost entirely of neutrons. 
A)  Neutron stars rotate from 1 to 30 times per second. 
B)  Neutron stars emit relatively narrow beams of light and other radiation. 
C)  Neutron stars contain strong gravitational fields but weak magnetic fields. 
D)  Neutron stars are composed almost entirely of neutrons.

Question 5

Which nuclear fusion cycle is the next one to begin after helium fusion ends in a massive star?

Accepted Answer

A)  carbon fusion 
B)  iron fusion 
C)  silicon fusion 
D)  oxygen fusion 
A)  carbon fusion 
B)  iron fusion 
C)  silicon fusion 
D)  oxygen fusion

Question 6

In the collapsing core of a high-mass star just before a supernova explosion occurs, the density is about that

Accepted Answer

A)  of degenerate gases in white dwarf stars, about 109 kg/m3. 
B)  of nuclear matter in a normal nucleus, about 4 *1017 kg/m3. 
C)  at the center of the Sun, about 1.5 *105 kg/m3. 
D)  of iron, 7.5 *103 kg/m3. 
A)  of degenerate gases in white dwarf stars, about 109 kg/m3. 
B)  of nuclear matter in a normal nucleus, about 4 *1017 kg/m3. 
C)  at the center of the Sun, about 1.5 *105 kg/m3. 
D)  of iron, 7.5 *103 kg/m3.

Question 7

The detection of neutrinos from SN 1987A occurred 3 hours before the detection of the burst of visible light. What caused this time lag?

Accepted Answer

A)  Neutrinos travel faster in vacuum than light does. 
B)  The space between the supernova and Earth is not a perfect vacuum but is filled with very rarefied gas and dust, which impedes the passage of light (very slightly) but not of neutrinos. 
C)  The neutrinos and the light were produced at the same time, but the light bounced back and forth between the core and the outer layers several times before these layers expanded to the point that they became transparent. 
D)  The neutrinos were produced earlier (when the core collapsed), and the light was produced 3 hours later (when the shock wave reached the outer layers). 
A)  Neutrinos travel faster in vacuum than light does. 
B)  The space between the supernova and Earth is not a perfect vacuum but is filled with very rarefied gas and dust, which impedes the passage of light (very slightly) but not of neutrinos. 
C)  The neutrinos and the light were produced at the same time, but the light bounced back and forth between the core and the outer layers several times before these layers expanded to the point that they became transparent. 
D)  The neutrinos were produced earlier (when the core collapsed), and the light was produced 3 hours later (when the shock wave reached the outer layers).

Question 8

Some magnetars with particularly strong magnetic fields emit huge bursts of high- frequency radiation as well as output at other wavelengths. Such magnetars are called

Accepted Answer

A)  soft gamma-ray repeaters. 
B)  hard gamma-ray repeaters. 
C)  neutron accretion disks. 
D)  ultrahigh-frequency sources. 
A)  soft gamma-ray repeaters. 
B)  hard gamma-ray repeaters. 
C)  neutron accretion disks. 
D)  ultrahigh-frequency sources.

Question 9

A stellar core of about 2 solar masses collapses inward in a supernova explosion. What is the result of this collapse?

Accepted Answer

A)  neutron star supported from further collapse by neutron-degeneracy pressure 
B)  black hole with infinitely small radius because nothing can prevent such a mass from collapsing completely 
C)  star a little smaller than the size of the Sun supported from further collapse by gas pressure from the hot interior of the star 
D)  white dwarf star supported from further collapse by degenerate-electron pressure 
A)  neutron star supported from further collapse by neutron-degeneracy pressure 
B)  black hole with infinitely small radius because nothing can prevent such a mass from collapsing completely 
C)  star a little smaller than the size of the Sun supported from further collapse by gas pressure from the hot interior of the star 
D)  white dwarf star supported from further collapse by degenerate-electron pressure

Question 10

SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter. Explain.

Accepted Answer

A)  The star that exploded was much smaller than a normal Type II supernova. 
B)  The star was surrounded by interstellar gas and dust that partially hid it from view from Earth. 
C)  The star contained considerably more heavy elements than most Type II supernovae, and these elements are believed to have absorbed many of the neutrinos produced in the core collapse. 
D)  The star that exploded was considerably cooler than a normal Type II supernova. 
A)  The star that exploded was much smaller than a normal Type II supernova. 
B)  The star was surrounded by interstellar gas and dust that partially hid it from view from Earth. 
C)  The star contained considerably more heavy elements than most Type II supernovae, and these elements are believed to have absorbed many of the neutrinos produced in the core collapse. 
D)  The star that exploded was considerably cooler than a normal Type II supernova.

Question 11

The first pulsar was detected with

Accepted Answer

A)  Galileo's telescope. 
B)  the infrared satellite IRAS. 
C)  a radio telescope being used by Cambridge University. 
D)  the 200-inch telescope at Mount Palomar. 
A)  Galileo's telescope. 
B)  the infrared satellite IRAS. 
C)  a radio telescope being used by Cambridge University. 
D)  the 200-inch telescope at Mount Palomar.

Question 12

The first pulsar was discovered in which year?

Accepted Answer

A)  1967 
B)  1930 
C)  1978 
D)  1054 
A)  1967 
B)  1930 
C)  1978 
D)  1054

Question 13

What fraction of its mass does a 25-solar-mass main-sequence star eject into space during its lifetime?

Accepted Answer

A)  almost all of it, greater than 80% 
B)  only a small fraction, about 1/100 
C)  between 1/4 and ½ 
D)  only its outer atmosphere, less than 1 part in 104 
A)  almost all of it, greater than 80% 
B)  only a small fraction, about 1/100 
C)  between 1/4 and ½ 
D)  only its outer atmosphere, less than 1 part in 104

Question 14

A white dwarf is a(n)

Accepted Answer

A)  object like Jupiter that was not quite massive enough to become a star. 
B)  small low-mass star no longer undergoing nuclear fusion. 
C)  type of small protostar. 
D)  hot, main-sequence star. 
A)  object like Jupiter that was not quite massive enough to become a star. 
B)  small low-mass star no longer undergoing nuclear fusion. 
C)  type of small protostar. 
D)  hot, main-sequence star.

Question 15

What is the Chandrasekhar limit?

Accepted Answer

A)  time limit of the existence of a planetary nebula, beyond which the nebula dissipates and becomes too rarified to see 
B)  time limit for the transfer of mass to a white dwarf in a close binary system, beyond which the white dwarf erupts in a nova 
C)  mass limit to the total mass of a white dwarf, beyond which it will erupt in a nova 
D)  mass limit to the total mass of a white dwarf, beyond which the electron degeneracy pressure will be overcome and the core will collapse 
A)  time limit of the existence of a planetary nebula, beyond which the nebula dissipates and becomes too rarified to see 
B)  time limit for the transfer of mass to a white dwarf in a close binary system, beyond which the white dwarf erupts in a nova 
C)  mass limit to the total mass of a white dwarf, beyond which it will erupt in a nova 
D)  mass limit to the total mass of a white dwarf, beyond which the electron degeneracy pressure will be overcome and the core will collapse

Question 16

What is photodisintegration?

Accepted Answer

A)  heating and ejection of mass from the surface of a normal star by the radiation from an orbiting neutron star 
B)  destruction of a star by the pressure of the radiation inside it 
C)  splitting apart of atomic nuclei by gamma rays 
D)  ejection of a neutron or proton from an atomic nucleus, accompanied by the emission of a gamma ray 
A)  heating and ejection of mass from the surface of a normal star by the radiation from an orbiting neutron star 
B)  destruction of a star by the pressure of the radiation inside it 
C)  splitting apart of atomic nuclei by gamma rays 
D)  ejection of a neutron or proton from an atomic nucleus, accompanied by the emission of a gamma ray

Question 17

The explosion of a supernova appears to leave behind

Accepted Answer

A)  a rapidly expanding shell of gas and a central neutron star. 
B)  a rapidly rotating shell of gas, dust, and radiation, but no central object. 
C)  a rapidly expanding shell of gas and a compact white dwarf star at its center. 
D)  nothing; the explosion changes all the matter completely into energy, which then radiates into space at the speed of light. 
A)  a rapidly expanding shell of gas and a central neutron star. 
B)  a rapidly rotating shell of gas, dust, and radiation, but no central object. 
C)  a rapidly expanding shell of gas and a compact white dwarf star at its center. 
D)  nothing; the explosion changes all the matter completely into energy, which then radiates into space at the speed of light.

Question 18

Which of these actions will a high-mass star (say, 25 times the mass of the Sun) NOT do at or near the end of its life?

Accepted Answer

A)  eject its outer layers and become a neutron star 
B)  convert silicon into iron in its core 
C)  emit copious amounts of neutrinos 
D)  eject its outer layers and become a white dwarf 
A)  eject its outer layers and become a neutron star 
B)  convert silicon into iron in its core 
C)  emit copious amounts of neutrinos 
D)  eject its outer layers and become a white dwarf

Question 19

Photodisintegration, the fissioning of iron nuclei into helium nuclei by high-energy gamma radiation, occurs only at the very end of the life of a massive star. Why can photodisintegration not occur earlier? Choose the statement that is NOT correct.

Accepted Answer

A)  Iron nuclei do not exist in anything but trace amounts before this stage. 
B)  Gamma radiation of sufficient energy is not produced before this stage. 
C)  The fissioning of an iron nucleus requires energy, and the energy-rich environment that allows fissioning to happen does not exist before this stage. 
D)  Under the conditions of the previous stages of evolution, iron (26Fe) disappears as quickly as it is formed by combining with helium (4He) to produce zinc (30Zn). 
A)  Iron nuclei do not exist in anything but trace amounts before this stage. 
B)  Gamma radiation of sufficient energy is not produced before this stage. 
C)  The fissioning of an iron nucleus requires energy, and the energy-rich environment that allows fissioning to happen does not exist before this stage. 
D)  Under the conditions of the previous stages of evolution, iron (26Fe) disappears as quickly as it is formed by combining with helium (4He) to produce zinc (30Zn).

Question 20

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses undergo a helium flash?

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

Hypernovae are associated with

During its time on the asymptotic giant branch, the Sun will eventually evolve into a red supergiant star with the brightness of _ and a diameter of _.

Which of these statements about novae is FALSE?

Which of these is NOT a typical property of young neutron stars?

Which nuclear fusion cycle is the next one to begin after helium fusion ends in a massive star?

In the collapsing core of a high-mass star just before a supernova explosion occurs, the density is about that

The detection of neutrinos from SN 1987A occurred 3 hours before the detection of the burst of visible light. What caused this time lag?

Some magnetars with particularly strong magnetic fields emit huge bursts of high- frequency radiation as well as output at other wavelengths. Such magnetars are called

A stellar core of about 2 solar masses collapses inward in a supernova explosion. What is the result of this collapse?

SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter. Explain.

The first pulsar was detected with

The first pulsar was discovered in which year?

What fraction of its mass does a 25-solar-mass main-sequence star eject into space during its lifetime?

A white dwarf is a(n)

What is the Chandrasekhar limit?

What is photodisintegration?

The explosion of a supernova appears to leave behind

Which of these actions will a high-mass star (say, 25 times the mass of the Sun) NOT do at or near the end of its life?

Photodisintegration, the fissioning of iron nuclei into helium nuclei by high-energy gamma radiation, occurs only at the very end of the life of a massive star. Why can photodisintegration not occur earlier? Choose the statement that is NOT correct.

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses undergo a helium flash?

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

Exam 14: The Death of Stars

Hypernovae are associated with

During its time on the asymptotic giant branch, the Sun will eventually evolve into a red supergiant star with the brightness of _____ and a diameter of _____.

Which of these statements about novae is FALSE?

Which of these is NOT a typical property of young neutron stars?

Which nuclear fusion cycle is the next one to begin after helium fusion ends in a massive star?

In the collapsing core of a high-mass star just before a supernova explosion occurs, the density is about that

The detection of neutrinos from SN 1987A occurred 3 hours before the detection of the burst of visible light. What caused this time lag?

Some magnetars with particularly strong magnetic fields emit huge bursts of high- frequency radiation as well as output at other wavelengths. Such magnetars are called

A stellar core of about 2 solar masses collapses inward in a supernova explosion. What is the result of this collapse?

SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter. Explain.

The first pulsar was detected with

The first pulsar was discovered in which year?

What fraction of its mass does a 25-solar-mass main-sequence star eject into space during its lifetime?

A white dwarf is a(n)

What is the Chandrasekhar limit?

What is photodisintegration?

The explosion of a supernova appears to leave behind

Which of these actions will a high-mass star (say, 25 times the mass of the Sun) NOT do at or near the end of its life?

Photodisintegration, the fissioning of iron nuclei into helium nuclei by high-energy gamma radiation, occurs only at the very end of the life of a massive star. Why can photodisintegration not occur earlier? Choose the statement that is NOT correct.

Consider a group of stars with masses up to 8 times the mass of the Sun. Stars of which masses undergo a helium flash?

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

During its time on the asymptotic giant branch, the Sun will eventually evolve into a red supergiant star with the brightness of _ and a diameter of _.