Astronomy Chpt 21, Stellar Explosions – Flashcards
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Beyond the formation of iron, nuclear energy can be produced only by
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fission of heavy nuclei back toward lighter ones
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As a star evolves, heavier elements tend to form by various processes. Which of the following is not one of these processes?
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neutronization
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Because they all involve the detonation of a carbon-rich white dwarf at Chandrasekhar's limit, all type I supernovae are equally luminous.
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true
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The Chandrasekhar mass limit is
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1.4 solar masses
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What made supernova 1987a so useful to study?
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All of the above are correct
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When helium capture occurs with a carbon 12 nucleus, what results?
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oxygen 16
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As a star's evolution approaches the Type II supernova, we find
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All of the above are correct
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For a nova to occur, the system must have already been a
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mass-transfer binary
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Which of these does not depend on a close binary system to occur?
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a Type II supernova
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Type I supernovae are NOT
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rich in hydrogen from the outer envelope of the collapsed star.
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The heaviest nuclei of all are formed
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by neutron capture during a type II supernova explosion.
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A recurrent nova could eventually build up to a
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Type I supernova
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A 20 solar mass star will stay on the main sequence for 10 million years, yet its iron core can exist for only a
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day
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Which of these is the likely progenitor of a type I supernova?
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a mass-transfer binary, with the white dwarf already at 1.3 solar masses
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The spectra of the youngest stars shows the most heavy elements present
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true
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The alpha process tends to produce chiefly
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even numbered elements
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Which of these events is not possible?
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white dwarfs and companion stars producing recurrent Type I supernova events
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In neutronization of the core, a proton and an electron make a neutron and a
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neutrino
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For a white dwarf to explode entirely as a Type I supernova, it's mass must be
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1.4 solar masses, the Chandrasekhar Limit.
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What direct evidence do astronomers have that supports the heavy element formation in stars?
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All of the above are evidence of this
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Most of the energy of the supernova is carried outward via a flood of
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neutrinos
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Nearly all the elements found in nature were formed inside stars, except for
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hydrogen and helium
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A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object?
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nova
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Which of these is the likely progenitor of a type II supernova?
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an evolved red giant which is just starting to make silicon in its core
