Astro 3

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Author:
ced78
ID:
270621
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Astro 3
Updated:
2014-04-15 04:23:13
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stellar evo
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astro1514
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  1. The masses of stars on the main sequence __________ from the      lower right to the upper left.
    increase
  2. The fundamental quantity which determines a star's central      pressure and temperature is its
    mass.
  3. The Russell-Vogt theorem (about chemical composition) states that the properties of a star      at any given age depend completely upon the star's
    mass and chemical composition.
  4. The lifetime of a star is determined by its initial
    mass and luminosity.
  5. Stars evolve because of changes in
    chemical composition of the core.
  6. The triple alpha reaction converts _________ into __________.
    c.  helium, carbon
  7. A nuclear reaction which occurs at sometime after hydrogen is      exhausted in the core is the
    triple alpha reaction.
  8. The temperature of a star's core will __________ as the star      fuses heavier elements.
    .  increase
  9. The evolution of a star depends primarily on the star's
    mass.
  10. Stars on the upper end of the main sequence next evolve into
    red giants.
  11. A T Tauri star is one which is
    variable and shedding mass.
  12. Protostars in dark, dusty regions may be studied in the      __________ spectral region.
    d.  infrared
  13. During the formation of a star, the contraction stops when
    c.  hydrogen burning becomes the dominant energy source.
  14. Hydrogen burning for a Sun-like star lasts approximately
    ten billion years.
  15. What types of stars are found on the zero-age main sequence
    newly formed stars
  16. When the hydrogen in the core of a star has been converted to helium, the core will next
    contract.
  17. Which of the following occurs during and immediately after the      phase of the hydrogen burning shell?
    the envelope expands and cools, and the star becomes a red giant
  18. As a degenerate gas is heated, it will
    neither expand nor contract.
  19. The ignition of helium in the degenerate core of a one solar mass star produces
    a helium flash.
  20. In a degenerate electron gas the outward pressure which keeps the star from collapsing is
    independent of temperature.
  21. Which of the following is NOT a characteristic of a red giant?
    cool core
  22. The horizontal branch is
    a helium core surrounded by a hydrogen burning shell.
  23. A planetary nebula is
    an expanding gas cloud that was ejected by a star.
  24. The stellar remnant of a one solar mass star is a
    white dwarf.
  25. High mass stars evolve more rapidly than low mass ones because the high mass stars
    b.  have higher core temperatures.
  26. In the most massive stars, the heaviest element which will be      produced in the core will be
    iron.
  27. Each time a form of nuclear fuel is exhausted in the core of a star, the star
    returns to the red giant branch
  28. The most mass a white dwarf can have is about
    1.4 Solar Mass.
  29. What element is observed in the spectra of Type II supernova?
    hydrogen
  30. A star which has a main sequence mass of 10 solar masses will most likely end up as
    a T Tauri star.
  31. If a neutron star has more mass than its mass limit, it will
    contract catastrophically.
  32. A black hole is called that because
    c.  photons can not be emitted from it.
  33. A neutron star's size is that of
    a typical city.
  34. The most massive stars are thought to end up as
    black holes.
  35. Heavy elements which are mixed into the material from which new generations of stars may come primarily from
    supernovae
  36. After the initial outburst of Supernova 1987A had diminished, the main source of luminosity was energy released from
    radioactive decay.
  37. What was the most energetic component of Supernova 1987A?
    the energy released in neutrinos
  38. Which of the following objects would have the highest gravitational redshift?
    a black hole
  39. A white dwarf will cool to become a black dwarf in several
    billion years.
  40. White dwarfs are composed mostly of
    degenerate gases.
  41. All novae are thought to involve a
    white dwarf.
  42. Novae explosions are caused by
    d. mass lost from a normal star falling onto a white dwarf companion.
  43. How can astronomers determine which type of supernovae they are observing?
    the spectral features are different
  44. The internal properties of a neutron star are most similar to those of a __________ star
    white dwarf
  45. Stellar remnants with masses between 2 and 3 solar masses will be
    neutron stars
  46. Pulsars are known to be
    d.  rotating neutron stars.
  47. Binary X-ray sources are known to be binary because
    eclipses are observed.
  48. The accretion disk surrounding a neutron star is very hot due to compression caused by gravitational forces. This implies the object will emit strongly in which spectral region?
    X ray
  49. If the Sun were suddenly to be replaced by a solar-mass black  hole the gravitational force on the Earth (1 A. U. away) would
    remain the same.
  50. The Schwarzschild radius of a black hole is
    b.  the distance from a black hole inside of which light cannot escape.
  51. From the outsider's point of view, in watching a star collapse to form a black hole, the collapse would appear to take
    forever.
  52. Which of the following lists the stellar remnants in order of decreasing maximum mass?
    black hole, neutron star, white dwarf
  53. A black hole is really
    strongly curved space.
  54. How is it possible to detect the presence of a black hole?
    .  by its effect upon other objects around it

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