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Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
Astronomy Stars 09
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Astronomy Stars 09

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A Power Point done by Kristen Hannan and myself for an 8th Grade unti on astronomy

A Power Point done by Kristen Hannan and myself for an 8th Grade unti on astronomy

Published in: Education
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  1. Astronomy Stars
  2. What is a Star? <ul><li>A large mass of gases </li></ul><ul><li>Most stars produce energy by nuclear fusion (converting Hydrogen to Helium) </li></ul>
  3. Star Color <ul><li>The spectrum (wavelengths of light produced by a star) is analyzed and the star is given a letter designation based on color and temperature </li></ul>
  4. Star Color Range <ul><li>O B A F G K M </li></ul><ul><li>Hotter---------------------------------------Cooler </li></ul><ul><li>Blue-White(OBAF) Yellow (G) Red(KM) </li></ul><ul><li>There are 10 divisions between spectral classes (each letter) 0-9 (ex: G0,G1,G2…….G9) </li></ul><ul><li>Our sun is a G2 star </li></ul>
  5. Luminosity <ul><li>=The actual brightness of a star </li></ul><ul><li>Depends on size and temperature </li></ul><ul><li>Distance from Earth is NOT a factor </li></ul><ul><li>Examples: </li></ul><ul><li>if 2 stars have the same temp, the larger star would be more luminous </li></ul><ul><li>If 2 stars were the same size but had different temps, the hotter star would be more luminous </li></ul>
  6. Apparent Magnitude <ul><li>= how bright a star appears to an observer on Earth </li></ul><ul><li>Depends on luminosity and distance </li></ul><ul><li>Brightest stars are 1 st magnitude; faintest stars (seen with naked eye) are 6 th magnitude </li></ul>
  7. Absolute Magnitude <ul><li>=the apparent magnitude of a star placed 32.6 light years from the sun </li></ul><ul><li>Astronomers use to compare brightness of different stars since all stars are different distances from Earth </li></ul><ul><li>Ex: Sun= 4.8 abs.mag (average star) </li></ul><ul><li> Rigel= -6.75 abs mag (very bright star) </li></ul>
  8. Hertzsprung Russell Diagram (H-R Diagram) <ul><li>A graph in which a star’s temperature is plotted against its absolute magnitude </li></ul><ul><li>Used to determine information about a star’s properties and life cycle </li></ul><ul><li>* see book p 626 </li></ul>
  9.  
  10. Red Giants <ul><li>Large, red stars that are cooler and more luminous than blue-white stars. </li></ul>
  11. Supergiants <ul><li>Large, low-density stars that are hundreds of times more luminous than red giants </li></ul><ul><li>*The largest of all stars </li></ul><ul><li>Ex: Betelgeuse (in Orion) </li></ul>
  12. Dwarf Stars <ul><li>Stars of absolute magnitude +1 or less </li></ul><ul><li>Most are red, yellow, blue (some white) </li></ul><ul><li>High density, hot, dim </li></ul>
  13. Nebula <ul><li>= A cloud of gas and dust where a star begins its life </li></ul>
  14. Supernova <ul><li>=The explosion of a large star </li></ul><ul><li>Millions of times brighter than the original star’s brightness </li></ul>

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