The Stars

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The Stars
2012-04-28 16:38:48
Asto1 Exam2

the stars
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  1. Which of the following four spectral-luminosity classes would correspond to a redsupergiant?
    M2 I
  2. Stellar parallax exists because
    the Earth moves in space.
  3. The star Alphard has an apparent magnitude of 2.0, and the star Megrez has anapparent magnitude of 3.3. The only thing that can be said with certainty about Alphard is that it
    is brighter than Megrez, as seen in our sky.
  4. What is the size of a star in the upper right part of the Hertzsprung-Russelldiagram compared to one in the middle of the diagram?
    It is larger.
  5. What is the physical reason for the appearance of periodic splitting andrecombining of spectral lines in the spectra of binary stars?
    Doppler shift of light from stars orbiting each other, moving toward and awayfrom Earth during this orbital motion
  6. All stars on the main sequence
    generate energy by hydrogen fusion in their centers.
  7. Small, hot, low luminosity stars are called
    white dwarfs
  8. As you drive along a road, trees in the foreground seem to shift in positionrelative to faraway hills. What name is given to this phenomenon?
  9. The luminosity of a star is
    the total energy emitted at all wavelengths into all space from its wholesurface.
  10. What is the spectral classifications of stars in correct order of increasing temperature?
  11. The Hertzsprung-Russell diagram is a statistical plot of which of the following two stellar parameters?
    luminosity and surface temperature
  12. As the brightness goes up........
    • The magnitude goes down
    • Brightest stars = 1st magnitude
    • Dimmest stars = 6th magnitude
    • o Brightest stars = 1st magnitude
    • Dimmest stars = 6th magnitude
  13. The Spectral Sequence
    • O = blue-violet (Hottest)
    • B = blue-white
    • A = white
    • F = yellow-white
    • G = yellow
    • K = orange
    • M = red-orange (Coolest)
    • o O = blue-violet (Hottest)
    • o B = blue-white
    • o A = white
    • o F = yellow-white
    • o G = yellow
    • o K = orange
    • o M = red-orange (Coolest)
  14. Luminosity Classes
    • I– Supergiants
    • II– Bright giants
    • III– Giants
    • IV– Subgiants
    • V– Main-sequence stars