Question: What is a pulsar?
Answer Choices:
a star that expands and contracts like a Cepheid.
a binary star system with a white dwarf star.
a rapidly rotating neutron star.
a star burning iron in its core.
Answer: a rapidly rotating neutron star.
Question: ____ stars are held up by electron degeneracy.
Answer: White dwarf
Question: How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?
Answer Choices:
It should orbit the galactic center at a much higher rate of speed.
It should have a higher fraction of elements heavier than hydrogen and helium.
It should be much brighter.
It should be higher in mass.
Answer: It should have a higher fraction of elements heavier than hydrogen and helium.
Question: What do astronomers consider ‘heavy elements’?
Answer Choices:
elements that are heavier than iron
all elements besides hydrogen and helium
elements that are heavier than uranium
elements that are heavier than carbon
Answer: all elements besides hydrogen and helium
Question: Which of the following is closest in size (radius) to a neutron star?
Answer Choices:
Earth
the Sun
a small city
a beach ball
Answer: a small city
Question: Harlow Shapley concluded that the Sun was not in the center of the Milky Way Galaxy by…
Answer Choices:
mapping the distribution of globular clusters in the galaxy.
mapping the distribution of stars in the galaxy.
mapping the distribution of gas clouds in the spiral arms.
looking at the phase of the “milky band” across the sky.
Answer: mapping the distribution of globular clusters in the galaxy.
Question: Suppose a binary star system consists of a white dwarf star that is gaining mass because of accretion from its companion star. When the white dwarf reaches a mass of 1.4 solar-masses what happens?
Answer Choices:
The white dwarf swells up and begins to fuse elements beyond carbon in its core.
A white dwarf can never gain enough mass to reach the limit because a strong stellar wind prevents the accreted from reaching it in the first place.
The white dwarf immediately collapses into a black hole, disappearing from view.
The white dwarf undergoes a catastrophic collapse, leading to a type of supernova that is somewhat different from that which occurs in a single massive star but is comparable in energy.
Answer: The white dwarf undergoes a catastrophic collapse, leading to a type of supernova that is somewhat different from that which occurs in a single massive star but is comparable in energy.
Question: An astronomer finds a star with surface temperature of 3000 K with a high luminosity. What kind of star is this?
Answer Choices:
Since Mars is so cool and with little energy even over a large square meter total, the only way that an M star can have a high luminosity is if it is very large (i.e., has a lot of square meters of surface area). This star is either a giant or a supergiant.
Since the star is an M type star it is cool. The luminosity is high because the star is probably close to Earth reflecting it appear much more luminous. The star is a red dwarf.
The star is a G2 main sequence star.
This star is probably a white dwarf with a cloud surrounding it that lowers the observed temperature and makes the star appear to have a high luminosity.
Answer: Since Mars is so cool and with little energy even over a large square meter total, the only way that an M star can have a high luminosity is if it is very large (i.e., has a lot of square meters of surface area). This star is either a giant or a supergiant.
Question: Most of the energy of a supernova is released in the form of…
Answer Choices:
visible light.
fusion reactions.
the physical destruction of the star.
neutrinos.
Answer: neutrinos.
Question: Which of the following [more than one] enriches the ISM with elements beyond iron?
Answer Choices:
Type II supernova
Iron stars
Type Ia supernova
Type Ib supernova
Answer: Type II supernova
Type Ia supernova
Question: ____ stars are held up by neutron degeneracy.
Answer Choices:
Main sequence
Neutron
Type Ib
White dwarf
Answer: Neutron
Question: The Sun’s location in the Milky Way Galaxy is ______.
Answer Choices:
at the very outer edge of the galactic disk.
in the halo of the galaxy, about 30,000 light-years above the galactic disk.
in the galactic disk, on the inside edge of the Orion Spur.
in the galactic disk, near the galaxy’s bulge.
Answer: in the galactic disk, on the inside edge of the Orion Spur.
Question: Who discovered the first pulsars?
Answer Choices:
Jocelyn Bell
Robert Dicke
Subrahmanyan Chandrasekhar
Ben Stein
Answer: Jocelyn Bell
Question: What causes the radio pulses of a pulsar?
Answer Choices:
The star’s orbiting companion periodically eclipses the radio waves emitted by the main pulsar.
A black hole near the star absorbs energy and re-emits it as radio waves.
As the star spins, beams of radio radiation sweep through space. If one of the beams crosses Earth, we observe a pulse.
The star undergoes periodic explosions of nuclear fusion that generate radio emission.
Answer: As the star spins, beams of radio radiation sweep through space. If one of the beams crosses Earth, we observe a pulse.
Question: What happens after the electron degenerate iron core of a high mass star collapses into a neutron degenerate core?
Answer Choices:
Type Ia supernova
Type Ib supernova
Neutrons are released and not much else
Type II supernova
Answer: Type II supernova
Question: A star of spectral class B2 undergoes core collapse and explodes in a supernova. What type of supernova is this?
Answer Choices:
Type Ia
Type Ib
Type II
Main sequence
Answer: Type II
Question: Which of the following is closest in size (radius) to a white dwarf?
Answer Choices:
The Sun
Earth
a small city
a beach ball
Answer: Earth
Question: Which of the following main sequence stars is most likely to end in a type II supernova?
Answer Choices:
K3V
G2V
M2V
O5V
Answer: O5V
Question: A type Ib supernova requires…
Answer Choices:
…that two neutron stars both be white dwarf stars.
…a binary system with a neutron star.
…a binary system with a white dwarf star.
…a massive star able to build up an iron core.
Answer: …a binary system with a white dwarf star.
Question: Elements up to iron are fused inside of high mass stars, but how are elements beyond iron created?
Answer Choices:
Nuclear reactions in the cooling core of a white dwarf can fuse with the iron core of a massive star in a binary star system to form elements heavier than iron.
Nuclear reactions in the brief period of a supernova explosion can form elements beyond iron.
Events heavier than iron are fused inside the cores of the most massive stars in the universe.
Iron fuses into heavier elements when the hydrogen burning shell is exhausted.
Answer: Nuclear reactions in the brief period of a supernova explosion can form elements beyond iron.
Question: SN 1987A is an example of a…
Answer Choices:
Type Ia supernova.
planetary nebula.
white dwarf.
Type II supernova.
Answer: Type II supernova.
Question: The maximum mass for a neutron star is…
Answer Choices:
not known exactly but is somewhere about 3 solar-masses.
somewhere about 5 solar-masses.
unlimited. There is no maximum limit.
1.4 solar masses.
Answer: not known exactly but is somewhere about 3 solar-masses.
Question: If a star’s degenerate core is greater than about ______ then nothing can stop the core from collapsing forever.
Answer Choices:
a bread box
3 solar-masses
1.4 solar-masses
the speed of light
2.1 solar-masses
Answer: 3 solar-masses