when a star dies, it becomes a supernova
A always
B only if it is a few times more massive than the sun
C only if it includes the whole galaxy
D never
type I supernovae are produced:
A when a high mass star gets to the iron fusion limit.
B when a star reaches the chandrasekhar limit.
C as the result of fusionable material being accreted by a white dwarf star from its binary companion.
D as a result of the helium flash in a 4 to 5 solar mass star.
type I supernovae occur in
A interstellar clouds.
B binary star systems.
C young star clusters.
D globular clusters.
a pulsar is
A a pulsating star
B a star which emits extremely regular pulses of radio waves
C a black hole capturing stars
D a star whose light output is controlled by intelligent life.
the crab nebula is
A a supernova remnant
B a newly forming star
C an h-2 region
D a black hole
we observe ordinary pulsars in what region of the spectrum
A x-ray
B radio
C optical
D infrared
how are elements with nuclei heavier than iron produced?
A they are produced in the same way as lighter elements by fusion of helium nuclei with heavier nuclei.
B they are produced during supernova explosions.
C they are produced by the interaction of the interstellar medium with material of planetary nebulae.
D they are produced by mass accretion of one member of a binary star from the other
member.
the inference that pulsars are rapidly-rotating neutron stars arises most strongly from the
A power of their pulses.
B regularity of their pulses.
C very short pulse periods of the fastest pulsars.
D detection of their pulses at radio wavelengths.
E detection of their pulses at optical wavelengths.
which of the following stars will eventually die in a supernova
A a main sequence star using the carbon cycle
B a star on the lower end of the main sequence
C a white dwarf
D a one solar mass red giant
an object of which of the following categories has the least density?
A main sequence stars.
B nebulae.
C pulsars.
D red giants.
E white dwarfs.
what phenomenon provides observational evidence for the existence of neutron stars?
A cepheids
B quasars
C planetary nebula
D pulsars
the supernova which exploded in 1054 is now
A visible as an expanding cloud of gas
B visible as a pulsar
C both a) and b)
D totally dissipated and invisible
heavy elements which are mixed into the material from which new generations of stars may be formed primarily come from
A the big bang
B planetary nebulae
C supernovae
D super-neutron stars
the crab nebula is
A the result of a supernova explosion
B a cool pre-stellar gaseous nebula
C a planetary nebula surrounding a hot star
D the nucleus of a spiral galaxy
a degenerate neutron core can be left by:
A the burnt-out core of any star.
B type I supernova explosions.
C type I and type II supernova explosions.
D type II supernova explosions.
the mass of a neutron star
A equals the mass of the original star from which it formed
B must be greater than 3 solar masses
C must be greater than 1 solar masses
D must be less than 3 solar masses
a type II supernova explosion
A involves a massive, population I star.
B blows off a large fraction of the star's mass.
C peaks about a month after the explosion begins.
D all of the above.
E none of the above.
we believe that pulsars slow down because
A they are converting energy of rotation into radiation.
B they are dragging companion stars around.
C of friction with the interstellar medium.
D of the conservation of angular momentum.
according to present theory, the pulses of radiation from a pulsar are due to
A pulsations of the surface of the star.
B pulsations from within the core of the star.
C eclipses of the star with a binary companion.
D rotation of the star.
E any of the above, depending upon the particular pulsar.
pulsars are observed in
A other galaxies
B the solar system
C supernova remnants
D regions of our galaxy with no associated object
where would you look for a pulsar, among the following locations in the universe?
A at the center of the galaxy
B in the crab nebula
C in the Orion nebula
D in the center of the sun
although neutron stars are very hot, they are not easy to locate because
A we cannot see inside the event horizon.
B most lie beyond dense dust clouds.
C solid neutron material cannot radiate photons.
D they have small surface areas.
a type II supernova is produced when:
A any star reaches the iron fusion limit.
B the collapse of a star's iron nucleus causes a shock wave that "blows off" the envelope of the star.
C an o or b main-sequence star evolves explosively to the red supergiant stage.
D an intermediate mass star reaches the "helium flash" stage in its evolution.
the crab nebula does not contain
A a proto star cloud
B a supernova remnant
C a pulsar
D a rapidly expanding cloud
pulsars are known to be
A pulsating white dwarfs
B pulsating neutron stars
C rotating white dwarfs
D rotating neutron stars
which of the following may not be considered evidence that the crab nebula is a supernova remnant?
A the crab nebula is found in the spot where observers long ago saw a very bright "new star."
B the filaments of gas in the crab nebula are expanding outwards at speeds that suggest an explosion at its center some time in the past.
C a very rapid pulsar has been discovered at the center of the crab nebula.
D the crab nebula is located in the constellation of Taurus the bull.
in our galaxy, as time goes on, the abundance of metals
A increases
B decreases
C remains the same
D no choice
stellar remnants with masses between 1.4 and 3 solar masses will be
A white dwarfs
B neutron stars
C black holes
D planetary nebulae
a pulsar is extremely regular because of its
A small size
B intense magnetism
C great distance
D rapid rotation
a neutron star
A will eventually become a black hole
B is the leftover remnant of a supernova explosion
C is the final state of all white dwarfs
D probably does not exist
the remnant of a supernova explosion is
A a black hole
B totally annihilated
C a white dwarf
D a neutron star imbedded in an expanding cloud of gas.
supernova in our galaxy are very rare because
A they are only visible when relatively close
B massive stars are rare
C binary stars are rare
D neutron stars are rare.
pulsars are
A larger and more massive than neutron stars.
B larger but less massive than neutron stars.
C smaller but more massive than neutron stars.
D smaller and less massive than neutron stars.
E the same as neutron stars.
you are comparing a typical nova explosion with that for a supernova. how do they differ?
A novas almost always occur in binary stars.
B novas involve explosions of the surface layers.
C novas leave behind most of the mass of the star.
D all of the above.
E none of the above.
stars which contribute most to the chemical enrichment of the interstellar medium are stars which are
A less massive than the sun
B solar mass stars
C more massive than the sun
D none of the above; stars do not enrich the interstellar medium, galaxies d
the heavy elements you are made of were formed in
A the big bang
B a supernova explosion
C the interior of a proto star
D the interior of a low mass star like the sun
a pulsar is
A a rotating neutron star
B a pulsating source of radio waves
C a star in the presupernova stage of expansion and contraction
D a black hole
in our galaxy, as time goes on, the abundance of heavy elements
A increases
B decreases
C remains the same
D none of the above
the crab nebula emits
A x-rays
B radio pulses
C visible light that does not approximate a black body
D all of these
we expect neutron stars to spin rapidly because
A they conserved angular momentum
B they have high orbital velocities
C they have high densities
D they have high temperatures
which of the following is the same as a neutron star?
A the crab nebula.
B a cepheid variable.
C a dark nebula.
D a pulsar.
E none of the above.
a crucial role that supernovas play in the scheme of cosmic evolution is that
A supernovas are the only source of neutrons.
B some elements heavier than iron are believed to be manufactured chiefly in supernovas.
C supernovas serve to disperse gas around the galaxy so that new stars can form.
D supernovas are a major source of light in most galaxies.
E supernovas have always been considered as omens that govern the affairs of man.
pulsars are found in
A other galaxies
B supernova remnants
C the solar system
D regions of our galaxy with no associated object
which of the following is not true.
A more energy is released in a supernova than a nova.
B in a nova, only the outer parts of the star explode.
C supernova explosions involve most of the star.
D supernovae occur only in binary star systems.
a pulsar is never associated with
A a white dwarf star
B a supernova remnant
C the crab nebula
D a neutron star
which of the following objects is smallest in size
A white dwarf
B sun
C neutron star
D Earth
a pulsar is composed mostly of
A hydrogen
B helium
C iron
D neutrons
the sun will never be
A a main sequence star
B a neutron star
C a white dwarf
D a red giant
most of the supernovae we see are
A in the neighborhood of the sun
B on our side of the galactic center
C on the other side of the galactic center
D in other galaxies
the only way a collapsing star's core can produce anything denser than a white dwarf is
A if it has sufficient density and temperature to fuse electrons with protons
B if it produces a nova explosion
C if it causes electrons to become degenerate
D none of the above; white dwarfs have the highest possible densities
it is very likely that a portion of the mass which composes our bodies was
A at one time a part of a main sequence star of mass equal to that of our own sun
B at one time a part of a supernova
C part of a neutron star which existed since the most recent "big bang"
D part of a black hole
about 7 billion years ago, the heavier atoms now found in your body most probably were
A in the star we call the sun, undergoing fusion
B part of the planet Earth
C part of a previous-generation star, which would lose at least some of its mass before dying
D part of the hot fireball that created the universe
which of the following will eventually die in a supernova
A a blue main sequence star
B a star on the lower end of the main sequence
C a white dwarf
D a one solar mass red giant
neutron stars are most commonly observed as
A pulsars
B quasars
C supernovae
D white dwarfs
the death of an "ordinary" star will result in a supernova only if
A it is less than 1.5 times the mass of the sun
B it is greater than 1.5 times the mass of the sun
C it is in a binary system
D it is formed without any fuel
which of the following does not occur as a result of a supernova explosion
A creation of complex elements
B creation of a planetary nebula
C formation of a neutron star
D bright flash of light
pulsars slow their pulse rate because
A they convert energy or rotation into radiation.
B they drag companion stars around, causing them to slow.
C of friction with the interstellar medium.
D of the conservation of angular momentum.
the most dense object known weighs
A one ounce per cubic inch
B one pound per cubic inch
C one hundred pounds per cubic inch
D many tons per cubic inch.
theory predicts that a neutron star should spin fast because
A it was given increased speed by the supernova explosion.
B it was given increased speed by a companion star.
C it conserved mass as it collapsed.
D it conserved angular momentum as it collapsed.
E the statement is false; they are not predicted to spin fast.
in the binary-star model for nova explosions, the hydrogen fuel from the explosion
A flows from a companion star to a white dwarf.
B flows from a companion star to a neutron star.
C flows from a companion star into a black hole.
D falls in from interstellar space.
which of the following is/are true of pulsars?
A pulsars have very strong magnetic fields.
B pulsars rotate very rapidly.
C pulsars are neutron stars.
D a, b, and c are all true.
a supernova is possibly triggered by
A a sudden and copious liberation of electrons
B the production of a core composed primarily of iron
C the sudden drop in temperature of a star's envelope
D the onset of the white dwarf stage
astronomers believe that up to 90 percent of a star's mass can be thrown o in a supernova explosion. one form that the rest of the star can take is a
A planetary nebula
B red giant
C neutron star
D black dwarf
the accretion disk surrounding a neutron star is very hot due to compression caused by gravitational forces. this implies the object will emit strong in which spectral region?
A x-ray
B ultraviolet
C visual
D infrared
a pulsar is
A a pulsating cepheid variable
B a pulsating neutron star
C a pulsating black hole
D pulsating radio signals from another civilization
which is not true of supernova remnants
A they are radio sources
B they have wispy filaments
C they are brighter than a whole galaxy
D they are made up of material thrown off by a dying star
pulsars typically fluctuate in brightness over a period of
A 1/10 second
B 10 seconds
C 10 minutes
D several hours
the very regular short-period pulses of radio radiation (that first brought pulsars to our attention) are now known to be connected with
A rapidly repeating star quakes on neutron stars
B rapidly rotating magnetized neutron stars
C matter falling into a black hole from an accretion disk
D the r-process of nuclear fusion
what supports a neutron star against its own weight?
A the exclusion principle prevents its electrons from being forced any close together
B the exclusion principle prevents its protons from being forced any closer together
C the exclusion principle prevents its neutrons from being forced any closer together
a pulsar is
A a rapidly rotating neutron star, emitting beams of radio energy
B a binary star in which matter from one star is falling onto the second sta
C an object at the center of each galaxy, which provides its energy by rapid rotation
D a pulsating star, in which size, temperature, and light intensity vary regularly
supernovae are observed only very rarely because
A the stars from which they form are quite rare
B the stars from which they form evolve very slowly
C they can be seen only when near by
D most go unnoticed
which is not a feature of a neutron star
A rapid rotation
B high magnetic field
C nuclear reactions in core
D supported by degeneracy pressure
pulsars were not discovered until 1967 because
A previous observations did not have sufficient time resolution
B they started in 1967
C radio astronomy started in 1967
D accurate clocks were not available to time the pulses
pulsars cannot be spinning white dwarfs because
A white dwarfs are not that common.
B white dwarfs are not dense enough.
C white dwarfs do not have magnetic fields.
D a white dwarf spinning that fast would fly apart.
a pulsar is believed to be
A a rotating neutron core that remains after a supernova explosion
B a white dwarf star with an unusually high spin rate
C a white dwarf star which radiates mainly in the radio frequencies
D none of the above
we believe that significant amounts of heavy elements (gold, silver, uranium etc.) are formed
A in white dwarfs
B in the cores of stars like the sun
C in the cores of stars in their late white dwarf stages
D in supernova explosions
the event which triggered the formation of the solar system was probably
A passage of a cloud of interstellar gas through a spiral arm of the galaxy
B a relatively nearby supernova explosion
C turbulence in a contracting proto star
D none of the above
the gravitational collapse of a star to form a neutron star during a supernova explosion causes
A the neutron star to spin much more rapidly than the original star did
B the neutron star to have a much stronger magnetic field near its surface t did the original star
C virtually all of its protons and electrons to merge and become neutrons
D all of the above
the most mass a neutron star can have is about
A 1.4 m
B 3 m
C 10 m
D none of the above; there is no limit to the mass
at its brightest, a typical supernova is
A 1000 times brighter than before
B as bright as the brightest stars
C as bright as a small galaxy
D only visible if in another galaxy
pulsars, emitting very regular radio pulses, are what type of object?
A pulsating variable stars
B black holes, with materials falling regularly into them
C binary star systems in which stars are undergoing regular eclipses as seen from Earth
D rapidly rotating neutron stars
the star at the center of the crab nebula is
A a pulsar
B a nova
C a white dwarf
D a black hole
the core of a star remaining after the supernova event may become a
A white dwarf
B neutron star
C black dwarf
D planet
a supernova is
A an explosion which blows a star apart
B visible as an object which may temporarily be as bright as an entire galaxy
C the source of most of the elements heavier than helium found in the Earth
D all of these
most of the heavy elements (beyond h and he in the periodic table) in our sun and solar system most probably originated
A from fusion reactions in the centers of stars which have now disappeared
B from chemical reactions in the planetary atmosphere
C in the original big bang of the universe
D from the center of our own sun, through fusion and later ejection as solar wind
which of the following is not a direct result of a supernova explosion
A formation of heavy elements
B creation of a neutron star or black hole
C a brief flash of light
D formation of new planets
astronomers currently believe that elements heavier than iron are created in
A the initial explosion of the universe
B degenerate white dwarfs
C supernova explosions
D they cannot be created at all
a star of very small size that emits radio pulses with very short regular periods is a
A quasar
B pulsar
C flare star
D dwarf nova
a pulsar is what type of object?
A a pulsating white dwarf star
B a rapidly rotating neutron star, producing beams of radio energy
C a small cepheid variable star
D a black hole, absorbing material in two streams
the pulsar "beeps" or "blinks" at us because of its rapid
A pulsation in size
B rotation
C fluctuation in temperature
D none of these
the density of a neutron star is
A about the same as that of a white dwarf
B about the same as that of the sun
C about the same as that of an atomic nucleus
D none of these
which kinds of stars are thought to go through a supernova type reaction?
A stars like the sun
B stars less massive than the sun
C stars considerably more massive than the sun
D none of these
where in the universe are heavy elements, with masses greater than that of iron, produced?
A in the surface layers of stars
B in the central cores of stars
C in the dark clouds of dust and gas
D in supernova explosions
the outward force supporting a neutron star against its own gravity is
A degenerate neutron pressure.
B internal pressure from heat.
C its rapid spinning.
D pressure from the outward flow of photons.
which of the following is not a general characteristic of a neutron star?
A size 10 - 20 kms
B density of 100 billion x water
C composed mostly of neutrons
D triple alpha process in core
E very strong magnetic field
in ad 1054, Chinese astronomers observed the appearance of a new star, whose location is now occupied by
A a supernova remnant.
B a pulsar.
C a neutron star.
D all of these.
which of the following support the idea that the crab nebula is a supernova remnant?
A Doppler shift observations show the filaments expanding.
B a pulsar lies in its center.
C the 1054 A.D. supernova occurred at the same place.
D all of the above.
E none of the above.
a pulsar is an example of a
A neutron star.
B white dwarf.
C variable star.
D black hole.
in ad 1054, Chinese astronomers observed the appearance of a new star, whose location is now occupied by
A an expanding cloud of gas
B a pulsar
C a neutron star
D all of these
a neutron star is formed
A in the center of a supernova explosion
B in the core of a star as the star evolves through its main sequence phase
C within a huge gas cloud, by collisions between stars
D just after the initial star formation
a star will die by becoming a supernova only if
A it has a mass much less than that of the sun
B it has a mass considerably greater than that of the sun
C the core expands too rapidly
D fusion never is able to start in the star
which of the following elements are thought to be made only in a supernova explosion?
A helium.
B oxygen.
C carbon.
D nitrogen.
E uranium.
a neutron star's size is that of
A the Earth
B the Earth's orbit
C the state of Kansas
D a typical city
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