Question 1

Which of these is the likely progenitor of a type II supernova?

Accepted Answer

A)   a mass-transfer binary, with the white dwarf already at 1.3 solar masses
B)   a contact binary, with the neutron star at 2.3 solar masses
C)   an evolved red giant which is just starting to make silicon in its core
D)   two white dwarfs in a contact binary system
E)   an evolved blue supergiant that is about to experience the helium flashF) A) and B)
G) A) and C)

Question 2

An object in the sky brightens suddenly,but shows no hydrogen lines in its spectrum.It is most likely a(n) :

Accepted Answer

A)   comet.
B)   type I supernova.
C)   type II supernova.
D)   asteroid impact.
E)   stellar collision.F) B) and D)
G) A) and E)

Question 3

What are two differences observed between type I and type II supernovae?

Accepted Answer

Type I supernovae have very little hydro...

Question 4

Most of the energy of the supernova is carried outward via a flood of:

Accepted Answer

A)   gamma rays.
B)   helium nuclei.
C)   protons.
D)   neutrinos.
E)   positrons.F) A) and C)
G) All of the above

Question 5

The heaviest nuclei of all are formed:

Accepted Answer

A)   in the horizontal branch.
B)   in dense white dwarfs.
C)   during nova explosions.
D)   in the ejection of matter in the planetary nebula.
E)   in the core collapse that set the stage of type II supernovae.F) None of the above
G) C) and D)

Question 6

Because they all involve formation of iron in cores of massive stars,all type II supernovae are equally luminous.

Accepted Answer

A) True 
 B)False

Question 7

Iron nuclei are the most tightly bound nuclei,which is why their production leads to type II supernovae.

Accepted Answer

A) True 
 B)False

Question 8

For a nova to occur,the system must have already been a(n) :

Accepted Answer

A)   astrometric binary.
B)   detached binary.
C)   spectroscopic binary.
D)   mass-transfer binary.
E)   eclipsing binary.F) A) and B)
G) B) and C)

Question 9

The supernova that formed M-1,the Crab Nebula,was observed in:

Accepted Answer

A)   1572 AD by Tycho Brahe.
B)   1604 AD by Johannes Kepler.
C)   1054 AD by Chinese and Middle Eastern astronomers.
D)   1006 by observers in the southern hemisphere.
E)   about 9,000 BC by all our ancestors.F) B) and E)
G) B) and D)

Question 10

As seen in 1987,when two silicon 28 nuclei fuse,or when seven alpha particles are added to a Si-28 nucleus,the initial result in either case is:

Accepted Answer

A)   the shedding of bipolar planetary nebula shells.
B)   a nova explosion.
C)   iron 56.
D)   cobalt 56.
E)   nickel 56.F) A) and D)
G) B) and E)

Question 11

What made supernova 1987a so useful to study?

Accepted Answer

A)   We saw direct evidence of nickel to iron decay in its light curve.
B)   Its progenitor had been observed previously.
C)   In the Large Magellanic Cloud, we already knew its distance.
D)   It occurred after new telescopes, such as Hubble, could observe it very closely.
E)   All of the above are correct.F) A) and E)
G) A) and B)

Question 12

A 20 solar mass star will stay on the main sequence for 10 million years,yet its iron core can exist for only a:

Accepted Answer

A)   day.
B)   week.
C)   month.
D)   year.
E)   century.F) D) and E)
G) B) and C)

Question 13

At temperatures of ________ K,photons can split apart nuclei until only protons and neutrons are left in photodisintegration.

Accepted Answer

A)   ten million
B)   100 million
C)   one billion
D)   ten billion
E)   one hundred billionF) B) and C)
G) A) and E)

Question 14

The core of a highly evolved high mass star is a little larger than:

Accepted Answer

A)   our solar system.
B)   our Sun.
C)   Jupiter.
D)   Earth.
E)   a white dwarf.F) C) and D)
G) A) and D)

Question 15

Why does iron formation cause a high mass star to "have a heart attack"?

Accepted Answer

Iron is the most tightly bonded of all n...

Question 16

The spectra of the youngest stars show the most heavy elements present.

Accepted Answer

A) True 
 B)False

Question 17

What evidence is there that supernovae really have occurred?

Accepted Answer

A)   Crab Nebula
B)   supernova remnants
C)   existence of heavy radioactive elements in nature
D)   observations of the actual explosions
E)   All of the above.F) B) and E)
G) All of the above

Question 18

Which of these is the likely progenitor of a type I supernova?

Accepted Answer

A)   a mass-transfer binary, with the white dwarf already at 1.3 solar masses
B)   a contact binary, with the neutron star at 2.3 solar masses
C)   an evolved red giant which is just starting to make silicon in its core
D)   an evolved blue supergiant that is about to experience the helium flash
E)   a helium-neon white dwarfF) A) and B)
G) A) and C)

Question 19

Type II supernovae have little hydrogen in their spectra; it had been used up already.

Accepted Answer

A) True 
 B)False

Question 20

The Chandrasekhar mass limit is:

Accepted Answer

A)   0.08 solar masses.
B)   0.4 solar masses.
C)   1.4 solar masses.
D)   3 solar masses.
E)   8 solar masses.F) A) and D)
G) B) and E)

Exam 21: Stellar Explosions: Novae,Supernovae,and the Formation of the Elements

The supernova that formed M-1,the Crab Nebula,was observed in:

Correct AnswerverifiedShow Answer

The Chandrasekhar mass limit is:

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Which of these is the likely progenitor of a type II supernova?

Correct AnswerverifiedShow Answer

At temperatures of ________ K,photons can split apart nuclei until only protons and neutrons are left in photodisintegration.

Correct AnswerverifiedShow Answer

What are two differences observed between type I and type II supernovae?

Correct AnswerverifiedType I supernovae have very little hydro...View AnswerShow Answer

What made supernova 1987a so useful to study?

Correct AnswerverifiedShow Answer

Most of the energy of the supernova is carried outward via a flood of:

Correct AnswerverifiedShow Answer

The core of a highly evolved high mass star is a little larger than:

Correct AnswerverifiedShow Answer

An object in the sky brightens suddenly,but shows no hydrogen lines in its spectrum.It is most likely a(n) :

Correct AnswerverifiedShow Answer

Type II supernovae have little hydrogen in their spectra; it had been used up already.

Correct AnswerverifiedShow Answer

For a nova to occur,the system must have already been a(n) :

Correct AnswerverifiedShow Answer

Iron nuclei are the most tightly bound nuclei,which is why their production leads to type II supernovae.

Correct AnswerverifiedShow Answer

Why does iron formation cause a high mass star to "have a heart attack"?

Correct AnswerverifiedIron is the most tightly bonded of all n...View AnswerShow Answer

A 20 solar mass star will stay on the main sequence for 10 million years,yet its iron core can exist for only a:

Correct AnswerverifiedShow Answer

Which of these is the likely progenitor of a type I supernova?

Correct AnswerverifiedShow Answer

Because they all involve formation of iron in cores of massive stars,all type II supernovae are equally luminous.

Correct AnswerverifiedShow Answer

The spectra of the youngest stars show the most heavy elements present.

Correct AnswerverifiedShow Answer

The heaviest nuclei of all are formed:

Correct AnswerverifiedShow Answer

As seen in 1987,when two silicon 28 nuclei fuse,or when seven alpha particles are added to a Si-28 nucleus,the initial result in either case is:

Correct AnswerverifiedShow Answer

What evidence is there that supernovae really have occurred?

Correct AnswerverifiedShow Answer

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Type I supernovae have very little hydro...
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Iron is the most tightly bonded of all n...
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