Astronomy Chapter 8

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Astronomy Chapter 8
2012-04-17 20:19:14
ASTR 205

The Family of Stars- key terms and concept
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  1. Stellar parallax
    a way to measure stellar distance by how far it shifts against the background stars
  2. parsec
    the distance to a star whose parallaz is one second of arc
  3. flux
    a measure of the flow of energy out of a surface, usually applied to light
  4. absolute visual magnitude (Mv)
    intrinsic brightness of a star; the apparent visual magnitdue the star would have if it were 10 parsces away
  5. luminosity
    the total amount of energy a star radiates in one second
  6. Hertzsprung-Russell (H-R) diagram
    a plot of instrinsic brightness vs. surface temperature of stars
  7. main sequence
    the region of the H-R diagram running from upper left to lower right
  8. giant (star)
    large, cool, highly luminous star in the mid-to-upper right of the H-R diagram
  9. supergiant (star)
    exceptionally lumionous star; diamtere is 10 to 1000 times that of the sun
  10. red dwarf
    a faint, cool, low-mass, main sequence star
  11. white dwarf
    dying star that has collapsed to the size of Earth and is slowly cooling off, found in lower left of the H-R diagram
  12. lumoinsity classes
    categories of stars of similar lumionsity, determined by the widths of lines in their spectra
  13. spectroscopic parallax
    the method of determining a star's distance by comparing its apparent magnitude with its absolute magnitude as estimated from its spectrum
  14. binary stars
    pairs of stars that orbit around their common center of mass
  15. visual binary system
    a binary star system in which the two stars are seperately visible in the telescope
  16. spectroscopic binary system
    a star system in which the stars are too close together to be visible seperatley, bu we determine that there are two stars by seeing two spectra.
  17. eclipsing binary system
    a binary star system in which the stars eclipse each other
  18. light curve
    a graph of brightness vs. time
  19. mass-luminosity relation
    the relationship which states that the more massive a main-sequence star is, the more luminous it is