Astronomy 103 Exam 2 Review

Spring 2009 Which star is hoer, a G4 main sequence star or a G4 giant? A. The main sequence star B. The giant C. Both have the same temperature D. Cannot be determined from informaon given Which star is hoer, a G4 main sequence star or a G4 giant? A. The main sequence star B. The giant C. Both have the same temperature D. Cannot be determined from informaon given What would be an immediate indicator the Sun had stopped fusing hydrogen? A. The light we see would shi wavelengths into the ultraviolet. B. The Sun would blow off its outer layers as a planetary nebula. C. Solar observatories would see that the Sun’s core was rapidly shrinking. D. The amount of neutrinos observed from the Sun would suddenly change. What would be an immediate indicator the Sun had stopped fusing hydrogen? A. The light we see would shi wavelengths into the ultraviolet. B. The Sun would blow off its outer layers as a planetary nebula. C. Solar observatories would see that the Sun’s core was rapidly shrinking. D. The amount of neutrinos observed from the Sun would suddenly change. A helium flash: A. Occurs to all stars B. Occurs only if the star’s core is degenerate C. Creates a planetary nebula D. None of the above A helium flash: A. Occurs to all stars B. Occurs only if the star’s core is degenerate C. Creates a planetary nebula D. None of the above The main sequence is: A. The most stable phase of a star’s life B. Where stars fuse hydrogen into helium in their cores C. Comparavely shorter for higher mass stars D. All of the above The main sequence is: A. The most stable phase of a star’s life B. Where stars fuse hydrogen into helium in their cores C. Comparavely shorter for higher mass stars D. All of the above What is the heaviest element that fusion can produce in the cores of massive stars? A. Helium B. Silicon C. Iron D. Uranium What is the heaviest element that fusion can produce in the cores of massive stars? A. Helium B. Silicon C. Iron D. Uranium White dwarfs shine due to A. Hydrogen shell burning B. Core fission of heavy elements C. Reflecon of light from their companion star in a binary system D. None of the above White dwarfs shine due to A. Hydrogen shell burning B. Core fission of heavy elements C. Reflecon of light from their companion star in a binary system D. None of the above Protostars can best be observed in the A. Ultraviolet B. Infrared C. Visible D. X‐ray Protostars can best be observed in the A. Ultraviolet B. Infrared C. Visible D. X‐ray Which of these star clusters is the oldest? A. B.

C. D. They all have the same age Which of these star clusters is the oldest? A. B.

C. D. They all have the same age Not all visual binaries have observed Doppler shis. Why? A. Some will be at an angle where the stars are never moving directly toward or away from Earth. B. Some binary systems are staonary C. Some binary systems have very ellipcal orbits D. All of the above Not all visual binaries have observed Doppler shis. Why? A. Some will be at an angle where the stars are never moving directly toward or away from Earth. B. Some binary systems are staonary C. Some binary systems have very ellipcal orbits D. All of the above The net result of the p‐p chain is that __ hydrogen are turned into __ helium A. 1; 2 B. 3; 2 C. 4; 1 D. 4; 2 The net result of the p‐p chain is that __ hydrogen are turned into __ helium A. 1; 2 B. 3; 2 C. 4; 1 D. 4; 2 The reddest stars spend the most me on the main sequence because A. They are the most massive stars and have more hydrogen fuel B. Their core pressure and temperature are low so the rate of hydrogen fusion is low C. They are fully convecve D. B and C The reddest stars spend the most me on the main sequence because A. They are the most massive stars and have more hydrogen fuel B. Their core pressure and temperature are low so the rate of hydrogen fusion is low C. They are fully convecve D. B and C Why do we use Type Ia supernovae to make distance measurements? A. They all happen at the same distance from Earth B. The ones nearer to us are more luminous C. They all have the same mass and leave no remnant D. All of the above Why do we use Type Ia supernovae to make distance measurements? A. They all happen at the same distance from Earth B. The ones nearer to us are more luminous C. They all have the same mass and leave no remnant D. All of the above Granulaon on the photosphere of the Sun is the result of A. Dust parcles in the photosphere B. Distoron caused by light passing through the turbulent solar atmosphere C. Moons of large amounts of gas moving out from the interior of the Sun and then back in D. The Sun’s magnec field Granulaon on the photosphere of the Sun is the result of A. Dust parcles in the photosphere B. Distoron caused by light passing through the turbulent solar atmosphere C. Moons of large amounts of gas moving out from the interior of the Sun and then back in D. The Sun’s magnec field If black holes emit no light, how can we observe them? Which of the following observaon methods is not valid? A. Maer pulled off a companion star emits a characterisc X‐ ray spectrum as it falls toward the black hole. B. Companion stars suddenly disappear from view as they plunge into the black hole. C. Black holes can act as gravitaonal lenses, forming mulple images of objects beyond the hole. D. A star that wobbles in its proper moon can be exhibing evidence of its orbital moon around an unseen companion. If black holes emit no light, how can we observe them? Which of the following observaon methods is not valid? A. Maer pulled off a companion star emits a characterisc X‐ ray spectrum as it falls toward the black hole. B. Companion stars suddenly disappear from view as they plunge into the black hole. C. Black holes can act as gravitaonal lenses, forming mulple images of objects beyond the hole. D. A star that wobbles in its proper moon can be exhibing evidence of its orbital moon around an unseen companion. The internal structure of the Sun, from the center to the surface is A. Energy‐generang core, radiave region, convecon region B. Energy‐generang core, convecve region, radiave region C. Convecve core, chemically reacng region, radiave region D. Energy‐generang core, convecve region The internal structure of the Sun, from the center to the surface is A. Energy‐generang core, radiave region, convecon region B. Energy‐generang core, convecve region, radiave region C. Convecve core, chemically reacng region, radiave region D. Energy‐generang core, convecve region Which of these spectral classes correspond to the reddest stars? A. O B. F C. A D. G Which of these spectral classes correspond to the reddest stars? A. O B. F C. A D. G On an H‐R diagram a star is found to be evolving to the right at a constant luminosity. We know that the star is becoming A. Only larger B. Only smaller C. Both smaller and cooler D. Both larger and cooler On an H‐R diagram a star is found to be evolving to the right at a constant luminosity. We know that the star is becoming A. Only larger B. Only smaller C. Both smaller and cooler D. Both larger and cooler The difference between Type Ia and Type II supernova is A. Their masses B. Their ages C. Their chemical composions D. All of the above The difference between Type Ia and Type II supernova is A. Their masses B. Their ages C. Their chemical composions D. All of the above The mechanism that results in high rotaon rates for certain pulsars is probably A. mass exchange with a binary companion. B. collapse of the neutron star, similar to the way that a skater increases rotaon in a spin. C. mass loss from the neutron star, the remainder spinning faster as a result. D. the merger of a pair of neutron stars to form a single object. The mechanism that results in high rotaon rates for certain pulsars is probably A. mass exchange with a binary companion. B. collapse of the neutron star, similar to the way that a skater increases rotaon in a spin. C. mass loss from the neutron star, the remainder spinning faster as a result. D. the merger of a pair of neutron stars to form a single object. When material transfers from a companion to a white dwarf, we normally see a A. Supernova B. Nova C. X‐ray burster D. Gamma‐ray burster When material transfers from a companion to a white dwarf, we normally see a A. Supernova B. Nova C. X‐ray burster D. Gamma‐ray burster Two observers have two clocks, one at rest on the Earth’s surface and one at rest high above the Earth’s surface. Which statement is correct? A. Each observer will see the other's clock to be running slow with respect to the observer's own clock. B. Each observer will see the other's clock to be running fast with respect to the observer's own clock. C. Both observers agree: since the clocks are not moving with respect to each other the clocks run at the same speed and read the same me. D. Both observers agree: the clock near Earth is running slower than the clock high above Earth's surface. Two observers have two clocks, one at rest on the Earth’s surface and one at rest high above the Earth’s surface. Which statement is correct? A. Each observer will see the other's clock to be running slow with respect to the observer's own clock. B. Each observer will see the other's clock to be running fast with respect to the observer's own clock. C. Both observers agree: since the clocks are not moving with respect to each other the clocks run at the same speed and read the same me. D. Both observers agree: the clock near Earth is running slower than the clock high above Earth's surface. Which of the following evoluonary phases are in order from youngest to oldest? A. Protostar, red giant, main sequence, white dwarf B. Protostar, main sequence, white dwarf, neutron star C. Protostar, main sequence, red giant, white dwarf D. Protostar, planetary nebula, main sequence, supernova Which of the following evoluonary phases are in order from youngest to oldest? A. Protostar, red giant, main sequence, white dwarf B. Protostar, main sequence, white dwarf, neutron star C. Protostar, main sequence, red giant, white dwarf D. Protostar, planetary nebula, main sequence, supernova A planetary nebula is: A. The progenitor of a solar system B. What remains when a white dwarf explodes as a supernova C. A shell of gas ejected from a star late in its life D. The cloud from which protostars form A planetary nebula is: A. The progenitor of a solar system B. What remains when a white dwarf explodes as a supernova C. A shell of gas ejected from a star late in its life D. The cloud from which protostars form The stars Capella, Aldebaran, and Regulus have parallax angles of 0.079, 0.05, and 0.041 arcsec, respecvely. Which star is the farthest away? A. Capella B. Aldebaran C. Regulus D. Cannot be determined from informaon given The stars Capella, Aldebaran, and Regulus have parallax angles of 0.079, 0.05, and 0.041 arcsec, respecvely. Which star is the farthest away? A. Capella B. Aldebaran C. Regulus D. Cannot be determined from informaon given Why are there no stars of less massive than approximately 0.08 solar masses? A. They are sll contracng and haven’t yet reached the main sequence B. They cannot compress their cores to hydrogen fusion temperatures C. Their mass is so small that deuterium fusion blasts them apart D. None of the above Why are there no stars of less massive than approximately 0.08 solar masses? A. They are sll contracng and haven’t yet reached the main sequence B. They cannot compress their cores to hydrogen fusion temperatures C. Their mass is so small that deuterium fusion blasts them apart D. None of the above For main sequence stars, as temperature increases A. Mass increases B. Radius decreases C. Luminosity decreases D. None of the above For main sequence stars, as temperature increases A. Mass increases B. Radius decreases C. Luminosity decreases D. None of the above The Sun is supported against the force of its own gravity by A. Gas pressure B. The force exerted by escaping neutrinos C. Forces from magnec fields D. Rapid rotaon The Sun is supported against the force of its own gravity by A. Gas pressure B. The force exerted by escaping neutrinos C. Forces from magnec fields D. Rapid rotaon