Question 1

What is the difference between a helium flash and a helium shell flash?

Accepted Answer

A)  A helium flash occurs when the core becomes supported by electron-degeneracy pressure; a helium shell flash occurs when the helium shell becomes supported by electron-degeneracy pressure. 
B)  All stars with mass less than eight times the mass of the Sun undergo a helium flash, but only those between two and eight times the mass of the Sun undergo a helium shell flash. 
C)  A helium flash occurs just once; a helium shell flash can repeat many times. 
D)  A helium flash results in a supernova; a helium shell flash results on a planetary nebula. 
A)  A helium flash occurs when the core becomes supported by electron-degeneracy pressure; a helium shell flash occurs when the helium shell becomes supported by electron-degeneracy pressure. 
B)  All stars with mass less than eight times the mass of the Sun undergo a helium flash, but only those between two and eight times the mass of the Sun undergo a helium shell flash. 
C)  A helium flash occurs just once; a helium shell flash can repeat many times. 
D)  A helium flash results in a supernova; a helium shell flash results on a planetary nebula.

Question 2

When a solar-mass star is ejecting a planetary nebula,the temperature of its exposed core can reach 100,000 K.How does this temperature compare with the core temperature when the star is on the main sequence?

Accepted Answer

A)  The exposed core is cooler simply because it is exposed to the cold regions of space. 
B)  The exposed core is cooler because it is at the end of its fuel supply. 
C)  The exposed core is hotter because it was heated by helium fusion rather than hydrogen fusion. 
D)  The exposed core is hotter because it was heated by carbon-oxygen fusion rather than hydrogen fusion. 
A)  The exposed core is cooler simply because it is exposed to the cold regions of space. 
B)  The exposed core is cooler because it is at the end of its fuel supply. 
C)  The exposed core is hotter because it was heated by helium fusion rather than hydrogen fusion. 
D)  The exposed core is hotter because it was heated by carbon-oxygen fusion rather than hydrogen fusion.

Question 3

What important event was recorded by ancient Chinese astronomers in a.d.1054?

Accepted Answer

A)  a brilliant, worldwide auroral display 
B)  the appearance of a nearby nova explosion in the Milky Way Galaxy 
C)  a bright binary star undergoing eclipse 
D)  the appearance of a supernova, visible in daylight 
A)  a brilliant, worldwide auroral display 
B)  the appearance of a nearby nova explosion in the Milky Way Galaxy 
C)  a bright binary star undergoing eclipse 
D)  the appearance of a supernova, visible in daylight

Question 4

What is the likely final fate of a star of 30 solar masses when it is on the main sequence?

Accepted Answer

A)  The star will collapse and become a black hole. 
B)  The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage. 
C)  The degeneracy of the electrons within the star will prevent collapse below the diameter of a white dwarf. 
D)  The star will immediately split in two and become a binary star system. 
A)  The star will collapse and become a black hole. 
B)  The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage. 
C)  The degeneracy of the electrons within the star will prevent collapse below the diameter of a white dwarf. 
D)  The star will immediately split in two and become a binary star system.

Question 5

Why do astronomers believe the binary companions of the white dwarfs that produce Type Ia supernovae are MOST probably main-sequence stars?

Accepted Answer

A)  Only main-sequence stars have lifetimes that would allow them to fill their Roche lobes at the same time their companion (formed at the same time) is a white dwarf. 
B)  We detect white dwarf binaries mostly by the astrometric method of looking for a wobble in the primary star's motion. Only a main-sequence star would be massive enough for this wobble to be detected. 
C)  A smaller star would not be able to fill its Roche lobes, and a larger star would swallow the white dwarf before it could produce a supernova. 
D)  The supernova explosion will cause the atmosphere of the binary companion to glow. We do not detect enough afterglow to suggest a giant or supergiant as companion. 
A)  Only main-sequence stars have lifetimes that would allow them to fill their Roche lobes at the same time their companion (formed at the same time) is a white dwarf. 
B)  We detect white dwarf binaries mostly by the astrometric method of looking for a wobble in the primary star's motion. Only a main-sequence star would be massive enough for this wobble to be detected. 
C)  A smaller star would not be able to fill its Roche lobes, and a larger star would swallow the white dwarf before it could produce a supernova. 
D)  The supernova explosion will cause the atmosphere of the binary companion to glow. We do not detect enough afterglow to suggest a giant or supergiant as companion.

Question 6

If you were to pass inward through the event horizon of a black hole,you could:

Accepted Answer

A)  do nothing to prevent yourself from falling directly into the singularity at the center. 
B)  escape again provided that the black hole is spinning. 
C)  move outward within the black hole with a powerful rocket, thereby avoiding the singularity until your fuel ran out, but you could never escape back out through the event horizon. 
D)  avoid the singularity by going into orbit around it, but you could never move outward again from any particular orbit. 
A)  do nothing to prevent yourself from falling directly into the singularity at the center. 
B)  escape again provided that the black hole is spinning. 
C)  move outward within the black hole with a powerful rocket, thereby avoiding the singularity until your fuel ran out, but you could never escape back out through the event horizon. 
D)  avoid the singularity by going into orbit around it, but you could never move outward again from any particular orbit.

Question 7

How much brighter than its main-sequence luminosity will a Sun-like star become at the asymptotic giant branch (AGB)phase of its life?

Accepted Answer

A)  10 times brighter 
B)  10⁴ times brighter 
C)  twice as bright 
D)  10³ times brighter 
A)  10 times brighter 
B)  10⁴ times brighter 
C)  twice as bright 
D)  10³ times brighter

Question 8

A binary system is formed with a neutron star and another star that has overflowed its Roche lobe.How does the detection of this binary differ from the detection of an isolated neutron star?

Accepted Answer

A)  The outer layers of the larger star envelop the neutron star, so only the spectrum of the larger star is detected. 
B)  This binary may emit intense X-rays, while an isolated neutron star emits radio waves. 
C)  The interaction of the larger star with the neutron star may slow the neutron star's rotation to the point where it no longer rotates. We then see a steady radio beam rather than the series of pulses that the lighthouse model predicts for an isolated neutron star. 
D)  The spectrum of the larger star swamps the spectrum of the neutron star, thus showing a standard thermal blackbody spectrum. An isolated neutron star produces a nonthermal radiation spectrum. 
A)  The outer layers of the larger star envelop the neutron star, so only the spectrum of the larger star is detected. 
B)  This binary may emit intense X-rays, while an isolated neutron star emits radio waves. 
C)  The interaction of the larger star with the neutron star may slow the neutron star's rotation to the point where it no longer rotates. We then see a steady radio beam rather than the series of pulses that the lighthouse model predicts for an isolated neutron star. 
D)  The spectrum of the larger star swamps the spectrum of the neutron star, thus showing a standard thermal blackbody spectrum. An isolated neutron star produces a nonthermal radiation spectrum.

Question 9

What is remarkable about the supernova remnant Cassiopeia A?

Accepted Answer

A)  Cassiopeia A contains a binary neutron star system in which one neutron star is significantly more massive than the other. 
B)  Cassiopeia A is bright at all wavelengths from radio and visible light to X-rays. 
C)  Cassiopeia A is the nearest supernova remnant, located only about 300 ly from Earth. 
D)  Cassiopeia A shows that a supernova occurred in the Galaxy about 300 years ago, but there is no record of any supernova having been seen at that time. 
A)  Cassiopeia A contains a binary neutron star system in which one neutron star is significantly more massive than the other. 
B)  Cassiopeia A is bright at all wavelengths from radio and visible light to X-rays. 
C)  Cassiopeia A is the nearest supernova remnant, located only about 300 ly from Earth. 
D)  Cassiopeia A shows that a supernova occurred in the Galaxy about 300 years ago, but there is no record of any supernova having been seen at that time.

Question 10

In which order does a single star of about 1 solar mass progress through the various stages of evolution?

Accepted Answer

A)  planetary nebula, main sequence, neutron star, black hole 
B)  T Tauri, red giant, white dwarf, neutron star 
C)  planetary nebula, main sequence, red giant, white dwarf 
D)  T Tauri, main sequence, planetary nebula, white dwarf 
A)  planetary nebula, main sequence, neutron star, black hole 
B)  T Tauri, red giant, white dwarf, neutron star 
C)  planetary nebula, main sequence, red giant, white dwarf 
D)  T Tauri, main sequence, planetary nebula, white dwarf

Question 11

The existence of stars composed almost entirely of neutrons was first predicted by:

Accepted Answer

A)  Jocelyn Bell in 1967. 
B)  Stephen Hawking in 1985. 
C)  Fritz Zwicky and Walter Baade in 1933. 
D)  Albert Einstein in 1908. 
A)  Jocelyn Bell in 1967. 
B)  Stephen Hawking in 1985. 
C)  Fritz Zwicky and Walter Baade in 1933. 
D)  Albert Einstein in 1908.

Question 12

Which is a CORRECT and complete statement of Einstein's first postulate of special relativity?

Accepted Answer

A)  Your description of physical reality is the same regardless of the constant velocity at which you move. 
B)  Your description of physical reality is the same regardless of the direction in which you move, even if the speed changes. 
C)  Your description of physical reality is the same regardless of how you move. 
D)  Your description of physical reality is the same regardless of the constant speed at which you move, even if direction changes. 
A)  Your description of physical reality is the same regardless of the constant velocity at which you move. 
B)  Your description of physical reality is the same regardless of the direction in which you move, even if the speed changes. 
C)  Your description of physical reality is the same regardless of how you move. 
D)  Your description of physical reality is the same regardless of the constant speed at which you move, even if direction changes.

Question 13

Each of the following statements is true about novae EXCEPT ONE.Which is the exception?

Accepted Answer

A)  Novae occur when two white dwarfs collide. 
B)  Novae are named after the constellation and the year in which they are discovered. 
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 are named after the constellation and the year in which they are discovered. 
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 14

Stars that have ejected a planetary nebula go on to become:

Accepted Answer

A)  red giants. 
B)  supernovae. 
C)  protostars. 
D)  white dwarfs. 
A)  red giants. 
B)  supernovae. 
C)  protostars. 
D)  white dwarfs.

Question 15

In a binary star system,one component is found to have about 3 solar masses,the other about 7 solar masses.The 3-solar-mass star is visible from Earth,but the 7-solar-mass star is not.Theoretical considerations tell us that the 7-solar-mass star must be a:

Accepted Answer

A)  neutron star. 
B)  cool planetary object. 
C)  white dwarf. 
D)  black hole. 
A)  neutron star. 
B)  cool planetary object. 
C)  white dwarf. 
D)  black hole.

Question 16

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 17

What prevents a neutron star from collapsing and becoming a black hole?

Accepted Answer

A)  Gravity in the neutron star is balanced by an outward force due to neutron degeneracy. 
B)  Gravity is balanced in neutron stars by the outward centrifugal force produced by their rapid rotation. 
C)  Gravity in the neutron star is balanced by an outward force due to gas pressure, as in the Sun. 
D)  Neutron stars are solid, and, like any solid sphere, they are held up by the repulsive forces between atoms in the solid matter. 
A)  Gravity in the neutron star is balanced by an outward force due to neutron degeneracy. 
B)  Gravity is balanced in neutron stars by the outward centrifugal force produced by their rapid rotation. 
C)  Gravity in the neutron star is balanced by an outward force due to gas pressure, as in the Sun. 
D)  Neutron stars are solid, and, like any solid sphere, they are held up by the repulsive forces between atoms in the solid matter.

Question 18

What is the difference between a normal pulsar,which emits radiation in the radio range,and a pulsating X-ray source?

Accepted Answer

A)  A pulsating X-ray source combines the characteristics of an ordinary pulsar and a variable star. The surface pulsates in and out creating a pulsating source. 
B)  A pulsating X-ray source is a binary system of two pulsars in very rapid rotation around one another. We see the interference pattern of the two pulsar beams as a pulsating X-ray jet. 
C)  A pulsating X-ray source is an ordinary pulsar, but occasionally, when the neutron star experiences a glitch and the crust cracks, the hot interior is exposed and emits an intense beam of X-rays. 
D)  A pulsating X-ray source is a pulsar with a binary companion. Matter pulled off the companion spirals along the intense magnetic field of the pulsar, and its interaction with the surface produces X-ray jets. 
A)  A pulsating X-ray source combines the characteristics of an ordinary pulsar and a variable star. The surface pulsates in and out creating a pulsating source. 
B)  A pulsating X-ray source is a binary system of two pulsars in very rapid rotation around one another. We see the interference pattern of the two pulsar beams as a pulsating X-ray jet. 
C)  A pulsating X-ray source is an ordinary pulsar, but occasionally, when the neutron star experiences a glitch and the crust cracks, the hot interior is exposed and emits an intense beam of X-rays. 
D)  A pulsating X-ray source is a pulsar with a binary companion. Matter pulled off the companion spirals along the intense magnetic field of the pulsar, and its interaction with the surface produces X-ray jets.

Question 19

In this chapter,we are dealing with intermediate-mass stars.What are we using as the upper mass limit of this classification?

Accepted Answer

A)  0.4 M 
B)  2.0 M 
C)  8.0 M 
D)  16.0 M 
A)  0.4 M 
B)  2.0 M 
C)  8.0 M 
D)  16.0 M

Question 20

Astronomers believe the binary companions of the white dwarfs which produce Type Ia supernovae are probably:

Accepted Answer

A)  supergiants. 
B)  giants. 
C)  main-sequence stars. 
D)  other white dwarfs. 
A)  supergiants. 
B)  giants. 
C)  main-sequence stars. 
D)  other white dwarfs.

What is the difference between a helium flash and a helium shell flash?

When a solar-mass star is ejecting a planetary nebula,the temperature of its exposed core can reach 100,000 K.How does this temperature compare with the core temperature when the star is on the main sequence?

What important event was recorded by ancient Chinese astronomers in a.d.1054?

What is the likely final fate of a star of 30 solar masses when it is on the main sequence?

Why do astronomers believe the binary companions of the white dwarfs that produce Type Ia supernovae are MOST probably main-sequence stars?

If you were to pass inward through the event horizon of a black hole,you could:

How much brighter than its main-sequence luminosity will a Sun-like star become at the asymptotic giant branch (AGB)phase of its life?

A binary system is formed with a neutron star and another star that has overflowed its Roche lobe.How does the detection of this binary differ from the detection of an isolated neutron star?

What is remarkable about the supernova remnant Cassiopeia A?

In which order does a single star of about 1 solar mass progress through the various stages of evolution?

The existence of stars composed almost entirely of neutrons was first predicted by:

Which is a CORRECT and complete statement of Einstein's first postulate of special relativity?

Each of the following statements is true about novae EXCEPT ONE.Which is the exception?

Stars that have ejected a planetary nebula go on to become:

In a binary star system,one component is found to have about 3 solar masses,the other about 7 solar masses.The 3-solar-mass star is visible from Earth,but the 7-solar-mass star is not.Theoretical considerations tell us that the 7-solar-mass star must be a:

The explosion of a supernova appears to leave behind:

What prevents a neutron star from collapsing and becoming a black hole?

What is the difference between a normal pulsar,which emits radiation in the radio range,and a pulsating X-ray source?

In this chapter,we are dealing with intermediate-mass stars.What are we using as the upper mass limit of this classification?

Astronomers believe the binary companions of the white dwarfs which produce Type Ia supernovae are probably:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Galaxies

Cosmology

Astrobiology

Filters

Exam 12: The Deaths and Remnants of Stars

What is the difference between a helium flash and a helium shell flash?

When a solar-mass star is ejecting a planetary nebula,the temperature of its exposed core can reach 100,000 K.How does this temperature compare with the core temperature when the star is on the main sequence?

What important event was recorded by ancient Chinese astronomers in a.d.1054?

What is the likely final fate of a star of 30 solar masses when it is on the main sequence?

Why do astronomers believe the binary companions of the white dwarfs that produce Type Ia supernovae are MOST probably main-sequence stars?

If you were to pass inward through the event horizon of a black hole,you could:

How much brighter than its main-sequence luminosity will a Sun-like star become at the asymptotic giant branch (AGB)phase of its life?

A binary system is formed with a neutron star and another star that has overflowed its Roche lobe.How does the detection of this binary differ from the detection of an isolated neutron star?

What is remarkable about the supernova remnant Cassiopeia A?

In which order does a single star of about 1 solar mass progress through the various stages of evolution?

The existence of stars composed almost entirely of neutrons was first predicted by:

Which is a CORRECT and complete statement of Einstein's first postulate of special relativity?

Each of the following statements is true about novae EXCEPT ONE.Which is the exception?

Stars that have ejected a planetary nebula go on to become:

In a binary star system,one component is found to have about 3 solar masses,the other about 7 solar masses.The 3-solar-mass star is visible from Earth,but the 7-solar-mass star is not.Theoretical considerations tell us that the 7-solar-mass star must be a:

The explosion of a supernova appears to leave behind:

What prevents a neutron star from collapsing and becoming a black hole?

What is the difference between a normal pulsar,which emits radiation in the radio range,and a pulsating X-ray source?

In this chapter,we are dealing with intermediate-mass stars.What are we using as the upper mass limit of this classification?

Astronomers believe the binary companions of the white dwarfs which produce Type Ia supernovae are probably:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Galaxies

Cosmology

Astrobiology

Filters