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STARS

STARS. BALL OF GASES, MOSTLY HYDROGEN AND HELIUM Are all stars the same color? NO! Color - determined by surface temperature. 1. Blue- young and hottest Ex. Rigel (above 30,000 degrees Celsius 2. White - usually old and hot Ex. Sirius (10,000 o C)

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STARS

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  1. STARS • BALL OF GASES, MOSTLY HYDROGEN AND HELIUM • Are all stars the same color? • NO! • Color- determined by surface temperature.

  2. 1. Blue- young and hottest • Ex. Rigel (above 30,000 degrees Celsius • 2. White - usually old and hot Ex. Sirius (10,000 oC) 3. Yellow – Average (5000-6000oC ) temperature and middle age • Ex. The sun

  3. 4 – Red- coolest and growing old • Ex. Betelgeuse less than 3,500oC

  4. All radiant energy that travels the speed of light in waves Ultraviolet ^ Infrared shortest longest Electromagnetic Spectrum

  5. Longest to shortest wavelength

  6. Spectroscope • Attaches to an optical telescope • Analyzes light from the stars Bright line spectrum

  7. Separates visible light by its different wavelengths • Each element is then identified by its own spectrum • Shows direction, movement and composition Spectrum___

  8. DOPPLER EFFECT **THE APPARENT SHIFT IN WAVELENGTH DUE TO A MOVING OBJECT Red shift- moving away Blue shift- moving toward

  9. DISTANCE LIGHT TRAVELS IN ONE YEAR • 6,000,000,000,000 MILES (186,000 mi/sec) or • 300,000 km/s • AU: Astronomical unit • Distance from Earth to Sun • 149,597,870,700 m or just 1 AU

  10. Distance is measured by using PARALLAX- • THE APPARENT SHIFT IN MOTION over time • Ex. • Hold out one arm and give a thumbs up • Close one eye and cover the Red Star • Now switch eyes • That apparent change is parallax!

  11. 2. Apparent Brightness (Magnitude) • A. The brightness we see from earth • B. Depends on size, distance and surface temperature.

  12. C. Star’s Brightness • 1. Luminosity or absolute magnitude. • A. Actual brightness of the star • B. found by using the distance and apparent magnitude.

  13. OPTICAL TELESCOPES 1. REFRACTING TELESCOPE **uses lenses to bend light to a focus point person

  14. 2. Reflecting Telescope • Uses mirrors • Concave mirror reflects light to a flat mirror • Ex. Hubble Space Telescope • Hale telescope

  15. 3. Catadioptric Telescope • Uses mirrors • AND Lenses • Ex. Celestron 8

  16. Problems with Optical telescopes • Light pollution

  17. EM (electromagnetic) spectrum

  18. Jansky 1905-1950 • Discovered radio waves in space 1931

  19. Reber- 1911-2002 • Built the first radio telescope (1937) Collects radio waves from space Can be used at anytime or weather

  20. VLA in New Mexico

  21. ASTRONOMICAL INSTRUMENTS

  22. Radio Telescopes • Operate in the radio frequency portion of the EM spectrum where they can detect and collect data on radio sources. • Used anytime, no light pollution or weather problems

  23. Scientific Terms a (testable) proposed explanation for a phenomenon a well-confirmed type of explanation of nature, made in a way consistent with scientific method describes some aspects of the universe or phenomenon Alvarez hypothesis “Meteor-impact” "Big Bang theory" “gravity”

  24. D. Classification • 1. H. R. diagram (Hertzsprung – Russell) • 2. Classifies by surface temperature and absolute magnitude. • 3. Main sequence stars- stars of similar composition and size • A. “average” stars

  25. 4. Outside of main sequence • A. Red super giants and red giants • B. Blue Giants. • C. White Dwarfs Betelgeuse

  26. Rigel Betelgeuse Sun Sirius

  27. E. Life Cycle Of Stars • STEP 1. Begins as a nebula- a cloud of dust and gas. (mostly H and He)

  28. STEP 2.Protostar- gravity forms a ball-shaped pocket and temperature increases.

  29. STEP 3. Nuclear fusion • 4 hydrogen fuse to make helium plus energy • Occurs in the core • Must be 10 mil • degrees C

  30. STEP 4. Main Sequence Star • Must have enough mass to have nuclear fusion for its energy

  31. STEP 5. RED GIANTS • Size of giants depends on the initial mass • Could be a super red giant like Betelgeuse • No more H(very little), He turns into C More energy HHe and HeC, gravity cant hold on ahhh!

  32. STEP 6. Supernova or white dwarf • a) white dwarf- small, hot, older star no shell, only core left to cool • 1. Ex. Sirius or the Sun (some day) • b) supernova- gigantic explosion of a large mass star like Betelgeuse • Chinese recorded one in 1054 AD

  33. Supernova Feb.24, 1987 170,000LY

  34. NEUTRON STAR 1. Extremely dense; like the mass of our sun into a 8 mi diameter

  35. d) Black hole- • 1. An object so dense that not even light can escape its surface

  36. Quasars- Very powerful source of energy most distant objects in space • Pulsars- • a neutron star that spins rapidly and sends out radio waves

  37. GALAXIES

  38. 3 TYPES • SPIRAL- 2-4 arms • EX. ANDROMEDA • IRREGULAR – • EX. MAGELLANIC CLOUDS • ELLIPTICAL

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