Astronomy Stars
What is a Star? <ul><li>A large mass of gases </li></ul><ul><li>Most stars produce energy by nuclear fusion (converting Hy...
Star Color <ul><li>The spectrum (wavelengths of light produced by a star) is analyzed and the star is given a letter desig...
Star Color Range <ul><li>O B A F G  K M </li></ul><ul><li>Hotter---------------------------------------Cooler </li></ul><u...
Luminosity <ul><li>=The actual brightness of a star </li></ul><ul><li>Depends on  size  and  temperature </li></ul><ul><li...
Apparent Magnitude <ul><li>= how bright a star appears to an observer on Earth </li></ul><ul><li>Depends on  luminosity  a...
Absolute Magnitude <ul><li>=the apparent magnitude of a star placed 32.6 light years from the sun </li></ul><ul><li>Astron...
Hertzsprung Russell Diagram (H-R Diagram) <ul><li>A graph in which a star’s temperature is plotted against its absolute ma...
 
Red Giants <ul><li>Large, red stars that are cooler and more luminous than blue-white stars. </li></ul>
Supergiants <ul><li>Large, low-density stars that are hundreds of times more luminous than red giants </li></ul><ul><li>*T...
Dwarf Stars <ul><li>Stars of absolute magnitude +1 or less </li></ul><ul><li>Most are red, yellow, blue (some white) </li>...
Nebula <ul><li>= A cloud of gas and dust where a star begins its life </li></ul>
Supernova <ul><li>=The explosion of a large star </li></ul><ul><li>Millions of times brighter than the original star’s bri...
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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

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Astronomy Stars 09

  1. 1. Astronomy Stars
  2. 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. 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. 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. 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. 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. 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. 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>
  10. 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>
  11. 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>
  12. 13. Nebula <ul><li>= A cloud of gas and dust where a star begins its life </li></ul>
  13. 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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