AST 1002 Test 3, Fall 2003 QQ 1 Which of the following is an observed property of stars? AA S 1 (1) color index (2) luminosity (3) surface temperature (4) NVA (5) NVA QQ 2 Star A has apparent visual magnitude 4.3, while Star B's apparent magnitude is 7.6. Which of the following statements is correct? AA S 1 (1) Star A has greater apparent brightness than Star B. (2) Star B has greater apparent brightness than Star A. (3) To compare the two stars' apparent brightnesses we need to know their distances. (4) NVA (5) NVA QQ 3 The Harvard stellar spectral types in order of increasing surface temperature are AA S 1 (1) MKGFABO (2) ABFGKMO (3) OBAFGKM (4) NVA (5) NVA QQ 4 Which kind of binary star system cannot be used to determine the masses of the two stars? AA S 1 (1) astrometric (2) visual, distance known (3) eclipsing+double-line spectroscopic (4) NVA (5) NVA QQ 5 Which method for finding the distances of stars makes use of the Earth's orbital motion around the Sun? AA S 1 (1) trigonometric parallax (2) spectroscopic parallax (3) geocentric parallax (4) NVA (5) NVA QQ 6 Which part of the Hertzsprung-Russell diagram has the stars with the largest radii (sizes)? AA S 1 (1) upper right (2) lower right (3) lower left (4) upper left (5) NVA QQ 7 The main-sequence stars having the shortest lifetimes are those AA S 1 (1) at the upper end (2) at the lower end (3) near the middle, like the Sun (4) NVA (5) NVA QQ 8 The Cepheid and RR Lyrae variable stars belong to which of the following classes of variables? AA S 1 (1) pulsating (2) erupting (3) eclipsing (4) NVA (5) NVA QQ 9 The type of star cluster that has a wide range of H-R diagrams with different main-sequence turnoff points is the AA S 1 (1) open or galactic cluster (2) globular cluster (3) OB association (4) NVA (5) NVA QQ 10 Which of the following conditions favors the contraction of a gas and dust cloud to form stars? AA S 1 (1) high density (2) high temperature (3) low density (4) NVA (5) NVA QQ 11 The minimum mass of a main-sequence star, 0.08 solar masses, is determined by the effect of AA S 1 (1) electron degeneracy pressure (2) radiation pressure (3) magnetic pressure (4) NVA (5) NVA QQ 12 A low-mass star is a red giant (or subgiant) when it is at the evolutionary stage of AA S 1 (1) hydrogen shell-burning (2) hydrogen core-burning (3) helium shell-burning (4) helium core-burning (5) NVA QQ 13 A massive star (many times more massive than the Sun) explodes as a Type II supernova when it reaches the point of AA S 1 (1) nuclear exhaustion (2) helium core-burning ("helium flash") (3) carbon detonation (4) NVA (5) NVA QQ 14 The Chandrasekhar limit is the AA S 1 (1) maximum mass for a star supported by electron degeneracy pressure (2) maximum mass for a star supported by neutron degeneracy pressure (3) minimum mass for a star supported by electron degeneracy pressure (4) NVA (5) NVA QQ 15 Ordinary novae (as opposed to supernovae) are AA S 1 (1) white dwarfs in close binary systems with mass transfer (2) neutron stars in close binary systems with mass transfer (3) solar-mass stars undergoing the "helium flash" phenomenon (4) NVA (5) NVA QQ 16 Pulsars are AA S 1 (1) rotating magnetic neutron stars (2) pulsating white dwarfs (3) rotating white dwarfs (4) NVA (5) NVA QQ 17 The evolution of a very massive star will almost certainly end up with the star becoming a AA S 1 (1) black hole (2) white dwarf (3) neutron star larger than the Schwarzschild radius (4) NVA (5) NVA QQ 18 The X-ray source Cygnus X-1 is the most convincing example found so far of a AA S 1 (1) stellar black hole (2) supermassive black hole (3) primordial black hole (4) NVA (5) NVA QQ 19 Time dilation is the term in connection with black holes that refers to AA S 1 (1) the slowing down of time near the event horizon as seen by a distant observer (2) the speeding up of time near the event horizon as seen by an observer falling towards the event horizon (3) the stretching of objects by tidal forces near the event horizon (4) NVA (5) NVA QQ 20 The Sun's true position in the Milky Way, near the outskirts rather than at the center, was established by AA S 1 (1) Shapley (2) Hubble (3) Baade (4) NVA (5) NVA QQ 21 Which of the following typically has a nearly circular orbit inside the Milky Way? AA S 1 (1) an O star in the disk (2) a globular cluster in the halo (3) a red giant in the central bulge (4) NVA (5) NVA QQ 22 In the original (simple) version of the idea of stellar populations, Population II was AA S 1 (1) the old, metal-poor stars of the bulge and halo (2) the young, metal-rich stars of the disk (3) the old, metal-rich stars of the disk (4) NVA (5) NVA QQ 23 The Milky Way's rotation curve is flat (after a rise at small distances from the center). This implies that AA S 1 (1) there is a large amount of mass outside the Sun's orbit, mostly in the form of dark matter (2) the Milky Way's mass is concentrated at the center, like the Solar System's (3) the density of matter is pretty much the same everywhere inside the Milky Way (4) NVA (5) NVA QQ 24 The spiral arms of spiral galaxies are best traced using AA S 1 (1) O and B stars and H II regions (2) globular clusters (3) yellow main-sequence stars like the Sun (4) NVA (5) NVA QQ 25 The "grand design" of two well-defined spiral arms in spiral galaxies is thought to be explained by which theory? AA S 1 (1) density wave (2) sequential star formation (3) "windup" theory (4) NVA (5) NVA QQ 26 A spiral galaxy having a bar, a relatively large central bulge, and tightly wrapped spiral arms is classified on the Hubble system as AA S 1 (1) SBa (2) SBc (3) Sb (4) S0 (5) NVA QQ 27 The Hubble type of galaxy having the bluest color, the largest percentage of gas and dust, and the most active star formation is AA S 1 (1) Irr (amorphous) (2) E (3) S and SB (4) NVA (5) NVA QQ 28 Which of the following methods gives distances for the most distant objects? AA S 1(1) Tully-Fisher relation (2) Cepheid period-luminosity relation (3) main-sequence fitting (4) NVA (5) NVA QQ 29 The fundamental problem posed by quasars was AA S 1 (1) how to produce so much luminosity from such a small volume (2) how any object could have such a large redshift (3) why some are radio sources and some are not (4) NVA (5) NVA QQ 30 According to the Hubble Law, on average a galaxy's radial velocity AA S 1 (1) is greater the farther away it is (2) is smaller the farther away it is (3) depends on the Hubble type of the galaxy but not on the distance (4) NVA (5) NVA QQ 31 Quasars, radio galaxies, Seyfert galaxies and several other unusual types are all though to be related, under the heading of {\it active galactic nuclei}. The energy source for all these is thought to be AA S 1 (1) gravitational potential energy of a supermassive black hole (2) nuclear fusion of a large number of stars (3) matter-antimatter annihilation (4) NVA (5) NVA QQ 32 The presence of dark matter associated with clusters of galaxies was {\bf first} indicated by analysis of AA S 1 (1) the virial theorem applied to the galaxies moving around inside the clusters (2) rotation curves of spiral galaxies inside the clusters (3) gravitational lensing by the clusters (4) NVA (5) NVA QQ 33 Clusters of clusters of galaxies are referred to as AA S 1 (1) superclusters (2) voids (3) megaclusters (4) NVA (5) NVA QQ 34 The cosmological model based on general relativity with the cosmological constant equal to zero and a mass density greater than a certain critical value is the one which AA S 1 (1) expands more and more slowly until it stops and then begins to contract and has positively curved space (2) expands more and more slowly but never stops expanding and has negatively curved space (3) expands more and more slowly but never stops expanding and has space with zero curvature (flat space) (4) NVA (5) NVA QQ 35 Recent studies of the Universe's expansion using Type Ia (white dwarf) supernovae indicate that it is accelerating, not slowing down. The term used to explain the acceleration, which is not yet understood, is AA S 1 (1) dark energy (2) dark matter (3) dark space (4) NVA (5) NVA