ARTIFACT: LIFE CYCLE OF THE

STARS

By Zachary and Alba

Slides 3 through 12 is the life of a small to medium star.

This is a picture of a red giant star.

Nebula: The first step in a stars life.

Nebula is a big cloud of gas & dust where stars form.

This is a picture of the horse head nebula.

A nebula is considered the birthplace for stars.

This is a picture of the Helix nebula.

Protostar A protostar is a gaseous cloud of dust, gas

and atoms. Protostars either devolop into a Main

Sequence star or a Small Protostar.

This is a picture of the pillars of gas in the eagle nebula.

Small Protostars

A small protostar is a brown dwarf star. This star is to small to create enough

heat to start fusion. Since it can’t start fusion it doesn’t shine

brightly, so brown dwarf stars are very hard to see in the night sky.

These are pictures of a brown dwarf right next to another bigger star.

Main Sequence

In a main sequence star the protostar gains enough mass to begin fusion.

The protostar could gain mass from clouds it goes through and other smaller protostars.

All Main Sequence stars fuse hydrogen. A main sequence star will be a red giant

when the Main Sequence runs out of hydrogen.

Hydrogen fusion

Hydrogen fusion is when 4 hydrogen nuclei come together to make helium nuclei.

The fusion cycle releases energy inside the core of the sun.

This fusion cycle generates the energy for our sun in our universe.

Red Giant

A Red Giant is a Main sequence star that has ran out of hydrogen and begins to fuse helium. When this runs out of fuel, it will turn into a Planetary Nebula.

This is a picture of a red giant star.

Helium fusion

A kind of nuclear fusion. Helium fusion is also known as the tri-

alpha process.

Planetary Nebula

A Planetary Nebula is a red giant that completely stops fusing.

Since the star isn’t producing a pressure outward, the outer layers of the star are driven away.

A Planetary Nebula will turn into a White Dwarf.

White Dwarf A White Dwarf star is a left over core from

a star A White Dwarf may only be the size of the

Earth, but it has the mass of half of the sun.

Our sun will become a white dwarf after it runs out of fuel.

White dwarf stars are one of the densest forms of matter.

OR

Black Dwarf

A Black Dwarf is a White Dwarf that cools off over trillions of years until it no longer emits light.

There are no know Black Dwarf stars in the galaxy. Even if there were any we would not be able to see them because they are black.

This is a picture of a black dwarf against a star filled back round.

Slides 16 through 23 are slides of big stars.

Nebula

A nebula for a big star is the exact same as for small to medium stars.

A nebula is a massive cloud of dust and different gasses.

Protostar

A protostar for a massive star is the same as a small to medium star.

A protostar is a small star that will turn into a massive main sequence star.

This Is a picture of a protostar in the Eagle Nebula.

Massive main sequence star

Massive Main Sequence stars fuse hydrogen much faster than small or medium stars.

Since it fuses faster it runs out fuel so fast that it will turn into a Red Supergiant very quickly.

This is a picture of a massive main sequence stars layers.

Red Supergaint

Massive main sequence star that runs out of hydrogen and begins fusing helium, then carbon, then oxygen etc.

A Red Supergiant star will turn into a Supernova when it runs out of elements that it can fuse.

A Red Supergiant will only live in this phase for a hundred thousand to a million years. This may semm like a long time to us, but it is no time at all in a stars life.

Supernova

Fusion stops in the star. Since the star isn’t fusing, gravity takes over and the star collapses.

When the star collapses, there is a gigantic exlposion that rocks the universe.

This is a picture of 2 red supergiant stars colliding and producing a very big supernova.

Neutron Star

A neutron Star has a super dense core of a star that was left over after the explosion of a supernova.

A neutron star is only 10 to 15 miles in diameter; but have the mass of 1.5-2 times that of the Sun.This is a

picture of a neutron.

OR

Black hole

Stars that have masses of 25 to 50 times that of the sun form black holes after a supernova.

The left over core of the star is so dense that is causes gravity to collapse.

This is a picture of a black hole.

Websites Used!!!!!!!

http://www.historyoftheuniverse.com http://filter.case.edu/sjr16/advanced/star

s_nebula.html http://en.wikipedia.org/wiki/helix_nebula http://www.windows.ecar.edu

http://www.daviddarling.info/encyclopedia/B/blackdwarf.html

More Websites

www.astrophysicsspectator.com/.../stars/MainSequence.html

en.wikipedia.org/wiki/Main_sequence

http://www.sciencedaily.com/articles/r/red_supergiant.htm

http://aspire.cosmicray.org/labs/star_life/starlife_proto.html

http://en.wikipedia.org/wiki/Brown_dwarf

Other resources

Mr. Wildeboar’s slide show’s Our notes