Lifecycle of Stars

Lifecycle of Stars By: Mark and Jacob

Nebula • A nebula is a cloud of gas and dust in space. • Nebulae are the birthplaces of stars. There are different types of nebula. • Dark Nebula also exist. These are dense clouds of molecular hydrogen which partially or completely absorb the light from stars behind them.

Protostar • A protostar is one of the earliest stages in star format • It is a large object that forms from gas from a giant molecular medium. • Typically grows to the point of starting nuclear fusion.

Brown Dwarf • A sub-stellar object that’s mass is between that of a sun and a planet. • They aren’t really brown, they’re a very dull shade of red. • They cannot perform nuclear fusion because they are not hot enough

Main Sequence • The majority of the stars in out galaxy are main sequence stars • They are all undergoing the fusion of hydrogen to helium • It’s the middle of a stars life. • Main sequence stars consist of high density gas and fluid.

Hydrogen Fusion • Hydrogen atoms become extreamly hot. • They collide and fuse together to form a helium atom. • The fusion cycle releases energy

Red Giant • A large bright star with solar masses ranging from 0.5-1.o that is still in the late phase of stellar evolution. • Close to the end of a star’s life the temperature at the core of it makes the star grow larger

Helium Fusion • A helium atom has to reach extream temperatures to start fusion. • They collide as well and fuse to form a carbon atom. • This realases more energy than Hydrogen fusion • Occures in red giants/super giants

Planetary Nebula • They are formed by certain stars when they die. • They are a short phenomenon, lasting only about a few ten thousand years • They hold an abundant amount of chemicals • They are very faint, cannot be seen with the naked eye

White Dwarf • A star that has exhausted all it’s nuclear fuel. • A typical white dwarf has half the mass of the sun, and is only a bit larger than the earth • They are one of the densest stars in existence, supassed by neutron stars

Black Dwarf • Black Dwarfs consist of cold and degenerate matter • It is thought that it would take a star at least a trillion years to cool down to become a black dwarf star. • It cannot emit heat or light.

Massive Main Sequence • The same events take place in a normal main sequence. • This sequence does not last as long as a normal main sequence would. • They burn through helium and hydrogen much faster, which is the cause of they’re short life span

Red Supergiant • It has 10 times the mass of the sun. • It’s lifespan can be anywhere from a few hundred thousand to one million years long • Only about 200 red supergiants have been found in the galaxy • They end in a massive explosion called a supernova.

Supernova • A supernova is a stellar explosion • The explosion is so bright it is able to light up a whole galaxy • The star loses most or all of it’s material KABOOM!!!!

Neutron Star • Results from a dead star • It is made by a gravitational collapse in a supernova • Neutron stars are extremely hot • It’s mass is between 1.35 and about 2.1 solar masses

Black Hole • It’s believed that black holes are made by massive stars when they die off. • Nothing, not even light, can escape from a blackhole. • A black hole’s density cannot be measured

Sources • Wikipedia.com • http://www.daviddarling.info/encyclopedia/B/browndwarf.html • http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971016.html • http://www.daviddarling.info/encyclopedia/B/blackdwarf.html • http://en.wikipedia.org/wiki/Black_hole

More Sources • http://en.wikipedia.org/wiki/Neutron_star • http://en.wikipedia.org/wiki/Main_sequence • http://en.wikipedia.org/wiki/Brown_dwarf • http://en.wikipedia.org/wiki/Supernova • http://en.wikipedia.org/wiki/Red_supergiant • http://en.wikipedia.org/wiki/Hydrogen_fusion • http://en.wikipedia.org/wiki/Planetary_nebula • http://en.wikipedia.org/wiki/White_dwarf

Even more Sources • http://en.wikipedia.org/wiki/Red_giant

Lifecycle of Stars