THE STARS

Melisa López y Eduardo Juarez

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

1.What it is?

Is a massive , luminous sphere of plasma held

together by gravity.

AgeBetween 1.000-10.000 million years old

Chemical composition71% hydrogen and 27% helium

Diameter20 to 40 km

ColoursRed, yellow, white, bluish-white,bluish

2.Life Cycle

• Introduction:- Interactions in the nucleus

- Increase in size

- Last stage: collapse

- Supernova

(Supernova)

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

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

4. Stellar structure and Composition

• Nucleus

• Mantle

• Atmosphere

Energy

Chromosphere

Photosphere

Solar Crown

Composition

• 75% Hydrogen, 23% helium and 2% other elements.

• Old Star = A little bit of metallicity Young Star = Many metallicity

• ClassificationPopulation I

Population II

(Young Star with a very high metallicity)

5. Classification• Introduction- Hiparco de Nicea's classification- Spectral type

•Spectral types

-Classification- Types of stars- Colors

- Luminosity- Types- Percentages

•Luminosity classes

Types of StarsType M Star

Type K Star

Type G Star

Type A and F Stars

6. POWER GENERATION IN THE STARS

- Sir Arthur Eddington explanation

- Hans Bethe explanation

- Fusion nuclear reactions(Energy produce by a Star)

7.Prototypical Star

- Sun

- Solar units

8. Stellar Mythology and Star SignA star can be …

The soul of a person Gods and Godesses