By: Mar, Patricia and Hanna.

Life of Stars

How is a Star Born?

Gas Giant

Brown Dwarf

Star

Classification:

MM

=

FUN FACT: Giant Molecular Clouds, or Nebulae can span 100 to even 600 light years in diameter!

The Life Cycle of an Average Star – Birth:

• The life cycle of an average star begins with its birth. They develop from giant molecular clouds.

• Giant Molecular Clouds are big and cold collections of gas and dust. When they collapse on themselves, stars begin the birthing process. They start out as protostars and turn into main sequence stars.

The Life Cycle of an Average Star – The Middle Years:

• The way a star generates heat and light is pretty simple, through the process of nuclear fusion.

• Nuclear fusion is mostly simply described in one of the most famous equations of all time; mass energy equivalence: E=mc2, by Albert Einstein.

• Nuclear fusion is the process in which hydrogen atoms turn into helium.

TheLife Cycle of an Average Star – The Golden Years:

The Red Giant Phase:As the star’s core contracts and its outer layers expand, its heat and light decreases. The helium atoms in the star’s core begin to fuse together, releasing energy again!

Planetary Nebula Phase:Its outer layers keep expanding. Eventually the outer layers drift out to space. As the star loses its outer layers, the star continues to cool off and decrease in size.

• When our Sun begins this process, we’ll be toasted!

TheLife Cycle of an Average Star – The Golden Years:

White Dwarf Phase:The star is in the state of radiating its remaining heat for up to billions of additional years.

Black Dwarf Phase:At this stage in the life cycle of an average star, it’s basically dead. A star will remain in the Black Dwarf state until forever.

MASSIVE STARS• Larger than 8 solar masses.

• PHASES:

1. Main sequence phase.

2. Short supergiant phase.

3. Spectacular death via a supernova

explosion.

It’s volume

is 5 billion times

greater tha the Sun.

MASSIVE STARSTHE MAIN LIFE SEQUENCE

• The life span of stars depend on their size.

• Very massive stars will become blue giants during their main sequence

• Balance between gravitational inward forces (centripetal force) and the core nuclear outward forces (pressure).

• Its hydrogen will only last for millions of years. BLUE GIANTSmaller stars

live billions

of years.

Our Sun is in its main

sequence.

MASSIVE STARSRED SUPERGIANT

• The star’s fuel will begin to run out.

• The massive star will become a red supergiant.

• This phase will last until the hydrogen is exhausted.

RED SUPERGIANT

Gravitational

inward forces.(hydrogen)

Fusion outwar

d forces.(helium

)

MASSIVE STARSSPECTACULAR DEATH

• If massive enough

SUPERNOVA

If the remaining mass is about 1.4 times that of our sun.

NEUTRON STAR

• If the remaining mass: 3 x Sun, it’ll collpase.

BLACK HOLE

BIBLIOGRAPHY

• http://astronomyisawesome.com/galaxies/life-cycle-of-an-average-star/

• www.skyandtelescope.com• http://www.universetoday.com/13507/what-is-the-biggest-

star-in-the-universe/• http://study.com/academy/lesson/massive-star-definition-

facts-life-cycle.html#lesson• http://slideplayer.com/slide/9391706/http://• www.space.com/22180-neutron-stars.html