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What is the net result of the proton-proton chain? a. 2 protons make deuterium + a neutrino b. 2 heliums are fused into 1 carbon, 1 neutrino + energy c. 4 hydrogens are fused into 1 helium, 2 neutrinos + energy d. 2 hydrogens and 1 helium are fused into 1 carbon + energy e. 3 helium-4 fuse to make carbon-12 By what mechanism does solar energy reach the Sun’s photosphere from the layer just below it? a. Differentiation b. Ionization c. Radiation d. Convection e. Conduction The number of sunspots and their activity peak about every: a. 36 days b. Six months c. year d. eleven years e. 76 years From where does most of the solar wind flow? a. Granules b. Sunspots c. Flares d. Prominences e. Coronal holes What is the meaning of the “solar constant”? a. The Sun’s position in the Milky Way is central and immobile b. The regularity of the solar cycle has not changed since Galileo c. The size of the Sun never changes d. The solar energy reaching Earth per unit area per unit time e. Like Venus, the surface appearance of the Sun is featureless The Sun spins on its axis roughly once each: a. Hour b. Day c. Month d. Year e. Eleven years The light we see from the Sun comes from which layer? a. Photosphere b. Troposphere c. Corona d. Chromosphere e. Ionosphere The temperature of the layer that produces the visible light of the Sun is: a. 300,000 K c d d e d c a e b. 12,300 K c. 15 million K d. 3,500 K e. 5,800 K The absolute magnitude of a star is its brightness as seen from a distance of: a. One million kilometers b. One astronomical unit (AU) c. One light year d. Ten parsecs e. Ten light years What are the two most important intrinsic properties used to classify stars: a. Mass and age b. Luminosity and surface temperature c. Distance and luminosity d. Distance and surface temperature e. Distance and color Stars that have masses similar to the Sun and sizes similar to the Earth are: a. Main sequence stars b. White dwarfs c. Red giants d. Horizontal branch dwarfs e. Brown dwarfs What property of the stars in a binary system can be determined by knowing the period of the stars’ common orbit and the distance between them? a. Their apparent brightness b. Their absolute magnitudes c. Their densities d. Their masses e. Their temperatures Giant and supergiant stars exceed most other stars in : a. Surface temperature only b. Luminosity only c. Radius only d. Both radius and luminosity e. Both surface temperature and luminosity A nearby star has a parallax of 0.2 arc seconds. What is its distance? a. 0.1 parsec b. 0.5 parsec c. 5.0 parsecs d. 50 parsecs e. 0.2 parsecs What physical property of a star does spectral type measure? a. Density b. Luminosity c. Composition d. Temperature e. Mass What is the typical main sequence lifetime of a G- d b b d d c d e type star? a. 1 billion years b. 100 million years c. 10 million years d. 100 billion years e. 10 billion years 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. All light is turned bluish in color d. It makes the light from stars appear to twinkle e. It ionizes the light and creates emission lines Interstellar gas is composed mainly of: a. Hydrogen b. Helium c. Carbon dioxide d. Methane e. Ammonia Some regions of the Milky Way appear dark because: a. There are no stars there b. Stars in that direction are obscured by interstellar gas c. Stars in that direction are obscured by interstellar dust d. The magnetic field has directed the polarized light away from these regions e. There are numerous black holes there that capture all of the star light behind them Why is 21-cm radiation so important to the study of interstellar matter and the Galaxy? a. It helps locate the galactic core in Orion b. Emitted by hydrogen, it passes through interstellar dust and lets us map the entire Galaxy c. Emitted by carbon dioxide, it passes through interstellar gas and lets us see places rich in organic molecules around the Galaxy d. It is emitted by most stars, enabling astronomers to map the stellar content of the Galaxy e. It is emitted only in hot regions of star formation, so the pattern of the spiral arms in the Galaxy can be mapped What makes the subject of star formation and evolution so difficult to study? a. It is so slow that no visible proof exists b. Star formation, in particular, is too expensive to study in detail c. Stars live too long to study them from birth to death d. Clouds, fragments, protostars, stars, and nebulae all interact and influence each other e. Shock waves disrupt the orderly evolution of a a c b c stars Evidence for stellar evolution comes from: a. Studies of molecules at close to absolute zero b. Tracking one star through time c. Plotting stars as they move about on the Hertzsprung-Russell diagram d. Studying different objects at different stages and piecing together an evolutionary picture e. Observations of dark and emission nebulae Why are star clusters almost ideal “laboratories” for stellar studies? a. All stars in the cluster are the same size and luminosity b. Their combined light makes them much easier to spot from a distance c. Stars in cluster have the same age, similar compositions, and are essentially at the same distance d. Stars in clusters are all relatively young and therefore shine brightly e. Like our Sun, stars in clusters are always located in the plane of the Milky Way Galaxy On the H-R diagram of clusters, which statement is NOT true? a. For young clusters, almost every star is still on the main sequence b. The brightest stars in old globular clusters are red giants c. The open clusters have as many members as the globular clusters, but spread their members stars over a much larger volume d. The turn-off point will be lower down the main sequence for older clusters e. We now observe the recent formation of open clusters, not globular clusters, in the Galaxy What inevitably forces a star like the Sun to evolve away from the main sequence? a. The core begins fusing iron b. The star uses up all of its supply of hydrogen c. The carbon detonation explodes it as a type I supernova d. Helium builds up in the core, while the hydrogen burning shell expands e. The core loses all its neutrinos, so all fusion ceases 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. White Dwarf d. Nova e. Black Hole What is used, observationally, to determine the age of a star cluster? d c c d c c a. Radioactive dating of isotopes seen in the spectra b. The number of main sequence stars c. The luminosity at the main-sequence turnoff d. The ratio of the number of giants to supergiants e. The number of white dwarf 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. Nova c. Gamma- ray burster d. Type I supernova e. Type II supernova The Chandrasekhar limit for the mass of a white dwarf is: a. 0.08 solar masses b. 0.4 solar masses c. 1.4 solar masses d. 3 solar masses e. 8 solar masses An iron core cannot support a star because: a. Iron is the heaviest element, and sinks upon differentiation b. Iron has poor nuclear binding energy c. Iron cannot fuse with other nuclei to produce energy d. Iron supplies too much pressure e. Iron is in the form of a gas, not a solid, in the center of a star What is the only way that a white dwarf can suddenly explode in a type I supernova? a. If it is a detached binary with a red supergiant b. If another star collides with it, such as with the blue stragglers c. If it passes through a large, dense dust cloud d. If it is a member of a mass-transfer binary e. If it finally cools off to under 2,000 K and collapses as a black dwarf A star spends most of its life as a: a. Protostar b. Main sequence star c. Planetary nebula d. Red giant or supergiant e. T Tauri variable star What evidence is there that supernova really have occurred? a. The Crab Nebula b. Supernova remnants c. Existence of heavy radioactive elements in nature d. Observations of the actual explosions e. All of the above Of the common elements in your body, the only one b c c d b e a NOT formed in stellar nucleosynthesis is: a. Hydrogen b. Carbon c. Oxygen d. Calcium e. Iron The Schwarzschild radius for a three solar mass black hole is: a. About three meters b. About 9 kilometers c. About the size of the Earth d. About the size of Jupiter e. Larger than our Sun What is the name of the most famous black hole candidate? a. Betelgeuse b. Scorpio X-1 c. Cygnus X-1 d. Sagittarius A e. Centaurus A The vast majority of pulsars are known only from their pulses in: a. Radio waves b. Microwaves c. Visible light d. X rays e. Gamma rays An object more massive than the Sun, but roughly the size of a city, is a: a. Supernova remnant b. White dwarf c. Brown dwarf d. Red dwarf e. Neutron star Which of the following can actually escape from inside a black hole’s event horizon? a. Very high energy gamma rays b. Gravitons c. Electrons d. Neutrinos e. None of the above What explanation does general relativity provide for gravity? a. Gravity is inversely proportional to the radius of the body b. Gravity can affect only massive particles, not massless photons c. Gravity is directly proportional to the mass of the attracting body d. Gravity is the opposite of the electromagnetic force e. Gravity is the result of curved spacetime Table 1. Sorting Table for Questions 1 b c a e e e 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Table 2. Numbers for questions