Term
The light we see from the Sun comes from which layer?
A) troposphere
B) ionosphere
C) corona
D) chromosphere
E) photosphere |
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Definition
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Term
Why couldn't you stand on the Sun's surface?
A) You could stand on it, if a sufficiently protective spacesuit could be designed.
B) The Sun's surface is too highly magnetized for anything to survive there.
C) The Sun doesn't have a solid surface.
D) You could stand on the surface.
E) The Sun has no surface at all...the photosphere is an illusion. |
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Definition
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Term
What is the net result of the proton-proton chain?
A) 3 helium 4 fuse to make C 12
B) 2 hydrogens and 1 helium are fused into 1 carbon + energy
C) 2 heliums are fused into 1 carbon, 1 neutrino + energy
D) 4 hydrogens are fused into 1 helium, 2 neutrinos + energy
E) 2 protons make deuterium + a neutrino |
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Definition
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Term
The critical temperature to initiate fusion via the proton-proton cycle in the cores of stars is:
A) 5,800 K
B) 3,000 K
C) 10 million K
D) 2,300,000 K
E) 100 million K |
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Definition
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Term
The pattern of rising hot gas cells all over the photosphere is called:
A) granulation.
B) filaments.
C) sunspots.
D) convective projections.
E) prominences. |
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Definition
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Term
When the chromosphere can be seen during a solar eclipse, it appears:
A) violet.
B) invisible.
C) red.
D) blue.
E) yellow. |
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Definition
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Term
The ________ Minimum was a period of solar inactivity between 1645 and 1715.
A) Maunder
B) Galileo
C) Spitzer
D) Schwarzschild
E) Hubble |
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Definition
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Term
The absolute magnitude of a star is its brightness as seen from a distance of:
A) one million kilometers.
B) one light year.
C) one astronomical unit.
D) ten parsecs.
E) 10 light years. |
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Definition
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Term
Perhaps the greatest of the Greek astronomers, ________ compiled the first catalog of stars, accurately measured their positions, and defined the basic system of stellar brightnesses.
A) Aristotle
B) Hipparchus
C) Aristarchus
D) Ptolemy
E) Erastothenes |
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Definition
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Term
Which statement about stellar motion is incorrect?
A) The radial velocity is measured by the Doppler shift.
B) In general, the closer a star is, the more its proper motion.
C) The transverse velocity is measured by the proper motion and the distance.
D) Like parallax, proper motion is measured over intervals of exactly six months.
E) The Pythagorean theorem relates space, transverse, and radial velocities. |
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Definition
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Term
Hipparcos' observations have given us good data on stars out to about:
A) 1000 light years.
B) 100 light years.
C) 200 parsecs.
D) 200 light years.
E) 1000 parsecs. |
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Definition
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Term
What is the absolute magnitude of our Sun?
A) -1.4
B) +4.8
C) -4.6
D) -26.7
E) +9.4 |
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Definition
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Term
What physical property of a star does the spectral type measure?
A) mass
B) density
C) luminosity
D) composition
E) temperature |
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Definition
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Term
Stellar masses are determined directly by observation of the orbits and periods of:
A) only eclipsing binary systems.
B) only spectroscopic binary systems.
C) only visual binary systems.
D) any binary system.
E) only astrometric binary systems. |
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Definition
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Term
Interstellar gas is composed mainly of:
A) hydrogen.
B) methane.
C) carbon dioxide.
D) helium.
E) ammonia. |
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Definition
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Term
Why are dark dust clouds largely misnamed?
A) All of the answer choices are correct.
B) They contain much more gas than dust.
C) The appearance of a cloud is an illusion; dust is scattered very evenly throughout the Galaxy.
D) They give off huge amounts of X and gamma rays due to their polarization.
E) Dust clouds are not dark but emit significant amounts of visible light. They just look dark compared to the bright stars. |
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Definition
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Term
Interstellar absorption lines are narrow primarily because:
A) the matter is at a low temperature, atoms are almost still.
B) All of the answer choices are correct.
C) molecules always produce narrow absorption lines.
D) there is very little interstellar matter.
E) most of the matter is ionized and atoms moving fast produce sharp lines. |
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Definition
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Term
What effect does dust have on visible light passing through it?
A) It dims and reddens it.
B) It completely blocks all visible light from passing through.
C) It ionizes the light and creates emission lines.
D) It makes the light coming from stars appear to twinkle
E) All light is turned bluish in color. |
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Definition
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Term
Which two ingredients are needed to make an emission nebula?
A) methane and ammonia
B) cool M giant stars and interstellar gas
C) hot O-B stars and interstellar gas
D) cool red stars and interstellar dust
E) interstellar gas and dust |
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Definition
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Term
Which statement about the dark nebulae is false?
A) Iron atoms probably help in the polarizing effect of the magnetic fields.
B) They comprise the majority of the mass of the whole Galaxy.
C) Their components are much like comet dust from the Oort Cloud.
D) Carbon and silicates are the chief absorbing and scattering agents.
E) They block the vast majority of our Galaxy from us in visual wavelengths. |
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Definition
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Term
An emission nebula appears primarily ___________ in color, due to ionized hydrogen.
A) blue
B) yellow
C) red
D) purple |
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Definition
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Term
What makes the subject of star formation so difficult and complex?
A) Shock waves disrupt the orderly evolution of stars.
B) Stars live too long to be observed from birth to death.
C) It is so slow that no visible proof of it exists.
D) Star formation is too expensive to study in detail.
E) Clouds, fragments, protostars, stars, and nebulae all interact and influence each other. |
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Definition
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Term
Which statement about the stages of starbirth is false?
A) By stage 7, the star has reached the main sequence.
B) By stage 3, the star has formed a photosphere.
C) The T-Tauri wind is prevalent in stage 5.
D) Nuclear reactions begin in the core by stage 4.
E) At stage 1, only the cloud exists. |
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Definition
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Term
In the collapsing cloud fragment stage (stage 2) of star formation, the size of the cloud fragment is about
A) the size of the Solar System.
B) 10 times the size of the Solar System.
C) 100 times the size of the Solar System.
D) 1/10th the size of the Solar System.
E) 1000 times the size of the Solar System. |
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Definition
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Term
Stage 4 of star formation is when the object can exhibit violent surface activity producing extremely strong protostellar winds. This phase is also called the
A) T-Tauri phase
B) protostar phase
C) protoplanetary nebula phase
D) Herbig-Haro phase
E) brown dwarf phase |
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Definition
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Term
What is the critical temperature at which hydrogen can fuse into helium in the star's core?
A) 100 million K
B) 26,000 K
C) 5,800 K
D) ten million K
E) one million K |
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Definition
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Term
If the initial interstellar cloud in star formation has a mass sufficient to form hundreds of stars, how does a single star form from it?
A) One star forms at its center and blows the rest of the matter back into space.
B) One star forms and the rest of the matter goes into making planets, moons, and other objects of a solar system.
C) The cloud is disrupted by rotation so that it reduces its mass down to that of a typical star.
D) The cloud fragments into smaller clouds and forms many stars at one time.
E) A supernova blows the cloud up and dissipates the majority of the gas. |
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Definition
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Term
At what stage of evolution do T Tauri stars occur?
A) after the star has established itself as a main sequence star
B) just prior to the protostar stage
C) when a protostar is on the verge of becoming a main sequence star
D) just as the collapsing cloud becomes luminous
E) just after the planetary nebula is expelled |
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Definition
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Term
A star spends most of its life:
A) as a main sequence star.
B) as a planetary nebula.
C) as a T Tauri variable star.
D) as a red giant or supergiant.
E) as a protostar. |
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Definition
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Term
The order of evolutionary stages of a star like the Sun would be Main Sequence, giant, planetary nebula, and finally:
A) hypernova.
B) neutron star.
C) black hole.
D) nova.
E) white dwarf. |
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Definition
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Term
What is a typical age for a globular cluster?
A) 12 billion years
B) 4.8 billion years
C) 200 million years
D) 10 million years
E) one billion years |
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Definition
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Term
What spectral type of star that is still around (not in a binary system) formed most recently?
A) M
B) F
C) A
D) O
E) K |
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Definition
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Term
Just as a low-mass main sequence star runs out of fuel in its core, it actually becomes brighter. How is this possible?
A) Helium fusion gives more energy than hydrogen fusion does, based on masses.
B) The core contracts, raising the core temperature and increasing the size of the shell of hydrogen burning.
C) Its outer envelope is stripped away and we see the brilliant core.
D) It immediately starts to fuse helium.
E) It explodes. |
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Definition
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Term
Which of these will the Sun probably become in the very distant future?
A) hypernova
B) nova
C) supernova
D) planetary nebula
E) pulsar |
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Definition
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Term
What characteristic of a star cluster is used to determine its age?
A) the ratio of main sequence to white dwarfs stars
B) the number of red giants
C) the total number of stars in the cluster
D) the main sequence turnoff
E) the faintest stars seen in the cluster |
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Definition
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Term
A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object?
A) hypernova
B) type II supernova
C) type I supernova
D) nova
E) gamma ray burstar |
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Definition
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Term
What evidence is there that supernovae really have occurred?
A) existence of heavy radioactive elements in nature
B) supernova remnants
C) All of the answer choices are correct
D) observations of the actual explosions
E) Crab Nebula |
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Definition
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Term
Which of these is the likely progenitor of a type I supernova?
A) an evolved blue supergiant that is about to experience the helium flash
B) a helium-neon white dwarf
C) a contact binary, with the neutron star at 2.3 solar masses
D) a mass-transfer binary, with the white dwarf already at 1.3 solar masses
E) an evolved red giant which is just starting to make silicon in its core |
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Definition
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Term
Most of the energy of the supernova is carried outward via a flood of:
A) neutrinos.
B) gamma rays.
C) protons.
D) helium nuclei.
E) positrons. |
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Definition
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Term
The making of abundant iron nuclei is typical of:
A) the helium flash.
B) type I supernovae.
C) type II supernovae.
D) planetary nebula ejection.
E) all novae. |
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Definition
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Term
What is stellar nucleosynthesis?
A) The formation of heavier elements inside stars.
B) The formation of planetary nebulae by red giants.
C) The formation of stars from a nucleus of contracting material.
D) The process by which stars form interstellar dust.
E) The formation of white dwarfs, neutron stars, and black holes from stars. |
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Definition
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Term
An iron core cannot support a star because:
A) iron supplies too much pressure.
B) iron is the heaviest element, and sinks upon differentiation.
C) iron has poor nuclear binding energy.
D) iron cannot fuse with other nuclei to produce energy.
E) iron is in the form of a gas, not a solid, in the center of a star. |
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Definition
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Term
The supernova of 1054 AD produced:
A) a remnant still visible to the naked eye, the Crab Nebula, M-1.
B) the most famous black hole.
C) the closest known neutron star to our Sun.
D) no remaining visible trace, as it was a type I supernova.
E) a pulsar with a period of 33 milliseconds, visible optically. |
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Definition
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Term
X-ray bursters occur in binary star systems. The two types of stars that must be present to make up such an object are:
A) a white dwarf and a main sequence star.
B) two neutron stars in a mass transfer binary.
C) a white dwarf and a neutron star.
D) a main sequence or giant star and a neutron star in a mass transfer binary.
E) a contact binary system of two red giants. |
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Definition
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Term
A proposed explanation for gamma-ray bursters is
A) hypernova-making black holes and bi-polar jets.
B) collisions between two white dwarfs
C) coalescence of a neutron star binary.
D) All of the answer choices are possible explanations. |
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Definition
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Term
Neutron stars have
A) monopolar fields that switch polarity every rotation.
B) very strong bi-polar magnetic fields.
C) no relation to pulsars.
D) weak or non-existent magnetic fields.
E) periods of days or weeks. |
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Definition
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Term
Which of the following can actually escape from inside a black hole's event horizon?
A) electrons
B) Nothing can escape from inside a black hole's event horizon.
C) gravitons
D) neutrinos
E) very high energy gamma-rays |
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Definition
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Term
Almost half of all known millisecond pulsars are found in what type of object?
A) supernova remnants
B) emission nebulae
C) giant molecular clouds
D) open clusters
E) globular clusters |
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Definition
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Term
What is the name of the most famous black hole candidate?
A) Cygnus X-1
B) Scorpio X-1
C) Betelguese
D) Sagittarius A
E) Centaurus A |
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Definition
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Term
The part of the Milky Way we are most familiar with is the:
A) Galactic Disk.
B) Halo.
C) Corona.
D) Galactic Bulge.
E) Galactic Center. |
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Definition
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Term
Most of the new star formation in the Milky Way Galaxy is found in the
A) globular clusters
B) bulge
C) halo
D) spiral arms
E) galactic center |
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Definition
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Term
Detailed measurements of the disk and central bulge region of our galaxy suggest that our Milky Way is a(n)
A) active galaxy
B) dusty irregular galaxy
C) Seyfert galaxy
D) very flat elliptical galaxy
E) barred spiral galaxy |
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Definition
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Term
It was the distribution of ________ that showed Harlow Shapley we were no where near the center of the Milky Way in the 1920s.
A) globular clusters
B) planetary nebulae
C) emission nebulae
D) supernova remnants
E) open clusters |
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Definition
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Term
For what type of object is the period-luminosity relation used for determining distances?
A) RR Lyrae variables
B) Planetary nebulae
C) Cepheids
D) Cataclysmic variables
E) T Tauri variables |
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Definition
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Term
What observation of the Galaxy suggests it is much larger than the halo and contains a large amount of matter not in the form of stars?
A) tidal streams in the halo
B) the shape of the spiral arms
C) infrared observations of the center of the Galaxy
D) the rotation curve
E) motions of the globular clusters |
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Definition
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Term
Which of the following is not typical of the Galaxy's spiral arms?
A) emission nebulae
B) giant molecular clouds
C) OB associations
D) globular clusters
E) young star clusters |
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Definition
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Term
An intermediately wound barred spiral galaxy would, in Hubble's system, be:
A) S2B.
B) SBb.
C) SIrr.
D) BS2.
E) BSE.5. |
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Definition
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Term
The greatest variation in size and mass occurs in which type of galaxy?
A) SB
B) Irr I
C) E
D) Irr II
E) Sc |
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Definition
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Term
Most galaxies in the Local Group are:
A) larger spirals than either the Milky Way or M-31 in Andromeda.
B) brown dwarfs, with even more dust than our own Galaxy.
C) dwarf spirals.
D) small irregulars similar to the Magellanic Clouds.
E) dwarf ellipticals, similar to the companions of M-31. |
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Definition
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Term
Which of the following paraphrases Hubble Law?
A) The greater the distance to a galaxy, the greater its redshift.
B) The greater the distance to a galaxy, the fainter it is.
C) The older the galaxy appears to us, the more luminous it is.
D) The more distant a galaxy is, the younger it appears.
E) The faster the galaxy spins, the more massive and luminous it is. |
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Definition
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Term
In active galaxies, the central engines may be temporarily fed by
A) a close encounter with a neighbor galaxy.
B) a sudden surge of star formation.
C) a series of supernovae around the core.
D) the sudden collapse of the core into a supermassive black hole.
E) the fusion of helium into carbon in their cores. |
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Definition
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Term
The most elongated of the elliptical galaxies are Hubble's class:
A) SE5.
B) E7.
C) SBE9.
D) F2.
E) E9. |
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Definition
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Term
The Magellanic Clouds are:
A) small irregular galaxies that move in orbit around our Milky Way.
B) the brightest H II regions in the sky, with active star formation.
C) spiral nebulae originally described by William Herschel.
D) the nearest of the globular star clusters.
E) dust clouds in the southern Milky Way near the Southern Cross. |
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Definition
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