Answer Options:
the speed at which a star moves transversely.
the star’s orbital period.
the force at which a star moves rapidly.
a star’s rotation rate.
Answer: a star’s rotation rate.
Question: Which of the following is closest in size (radius) to a white dwarf?
Answer Options:
The Sun
Earth
a small city
a beach ball
Answer: Earth
Question: Suppose the Sun were to be suddenly replaced by a black hole of one solar-mass. What would happen?
Answer Options:
It would get cold and dark, but probably little else.
There would be huge chaos. Human sacrifice, dogs and cats living together, mass hysteria!
The more massive planets, like Jupiter and Saturn would be most affected. These planets would travel to the inner solar system and change the orbits of the terrestrial planets.
The orbits of all the planets would be perturbed to the point that they would begin spiraling into the black hole.
Answer: It would get cold and dark, but probably little else.
Question: At the center of the Sun, fusion converts hydrogen into
Answer Options:
hydrogen compounds
helium
radiation and elements like carbon and nitrogen
radioactive elements like uranium and plutonium
helium, energy, and neutrinos
Answer: 5. helium, energy, and neutrinos
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 Options:
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: How do human-built nuclear power plants on Earth generate energy?
Answer Options:
chemical reactions
nuclear fusion
nuclear fission
converting kinetic energy into electricity
converting gravitational potential energy into electricity
Answer: 3. nuclear fission
Question: If the maximum mass of a white dwarf star is 1.4 solar-masses, then how is it possible for a 6 solar-mass star to end up as a white dwarf?
Answer Options:
The solar-mass star loses enough strong stellar winds and planetary nebulae.
The solar-mass star will divide into about 3 smaller stars, each with a small enough mass to become a white dwarf.
White dwarf stars can be larger than 1.4 solar-masses if they are not made of degenerate matter.
When fusion ends in the 6 solar-mass star, it will contract and become a 1.4 solar-mass white dwarf.
Answer: The solar-mass star loses enough through strong stellar winds and planetary nebulae.
Question: Which of the following would be most likely to show a main sequence turnoff point around F9?
Answer Options:
OB Stellar Association
Spheroid Cluster
Young Open Cluster
Globular Cluster
Answer: Globular Cluster
Question: Who showed that the Sun and stars are composed of mostly hydrogen?
Answer Options:
Lord Kelvin
Cecilia Payne-Gaposchkin
E. W. Maunder
Wolfgang Pauli
Answer: Cecilia Payne-Gaposchkin
Question: Which layer of the Sun do we normally see with our unaided eye?
Answer Options:
photosphere
corona
radiation zone
chromosphere
convection zone
Answer: photosphere
Question: The red giant stage occurs when…
Answer Options:
the star is finished burning helium in its core
the star stops hydrogen shell burning and reverts back to core fusion
hydrogen shell burning begins causing the star to expand, become more luminous, and have a cooler surface temperature
the star starts burning helium in its core
Answer: hydrogen shell burning begins causing the star to expand, become more luminous, and have a cooler surface temperature
Question: How do we know what goes on under the surface of the Sun?
Answer Options:
We have X-ray images from satellites of the interior of the Sun.
Astronomers create mathematical models that use the laws of physics, the Sun’s observed properties and laws, and computers to predict its internal conditions.
We have sent probes below the surface of the Sun.
By measuring Doppler shifts, we observe vibrations of the Sun’s surface that are created deep within the Sun.
By both creating mathematical models and measuring Doppler shifts.
Answer: 5. By both creating mathematical models and measuring Doppler shifts.