1. THE STARS Melisa López y Eduardo Juarez

2. CONTENT What it is? Life Cycle (Formation, evolution and death) Group and distribution Stellar structure and composition Classification Power generation in the stars Prototypical Star Stellar Mythology and Star Sign

3. 1.What it is? Is a massive, luminous sphere of plasma held together by gravity. Age Between 1.000-10.000 million years old Chemical composition 71% hydrogen and 27% helium Diameter 20 to 40 km Colours Red, yellow, white, bluish-white,bluish

4. 2.Life Cycle Introduction: -Interactions in the nucleus -Increase in size -Last stage: collapse -Supernova (Supernova)

5. 2.1 Formation, evolution and death -Produced in molecular clouds -Protostar - Nuclear reactions - End of life White dwarf Neutron star and black hole Gamma rays explosion

6. 3. Group and Distribution Bound Stars They Form a Binary Stellar System Isolated Stars Only obey the global gravitational camp Stellar Distribution The stars are distributed on Galaxies not in the Universe Spacial navigation and stellar positioning

7. 4. Stellar structure and Composition Nucleus Mantle Atmosphere Energy Chromosphere Photosphere Solar Crown

8. Composition 75% Hydrogen, 23% helium and 2% other elements. Old Star = A little bit of metallicity Young Star = Many metallicity Classification Population I Population II (Young Star with a very high metallicity)

9. 5. Classification Introduction - Hiparco de Nicea's classification - Spectral type Spectral types -Classification - Types of stars - Colors - Luminosity - Types - Percentages Luminosity classes

10. Types of Stars Type M Star Type K Star Type G Star

11. Type A and F Stars

12. 6. POWER GENERATION IN THE STARS - Sir Arthur Eddington explanation - Hans Bethe explanation - Fusion nuclear reactions (Energy produce by a Star)

13. 7.Prototypical Star - Sun - Solar units

14. 8. Stellar Mythology and Star Sign A star can be … The soul of a personGods and Godesses