Nebula
A nebula is the first step in a stars life. It is made up of a bunch of gasses that are created after a super nova. yet, there are many different types of nebulas. There are the planetary, supernova remnants, diffuse nebula and a herbig haro nebula. The planetary nebulas look like planets. And are made from the shell of a star that was in its red giant phase. While the supernova remnants are nebulas made of left over supernova, where the star exploded and left the gasses. Diffuse nebulas are very large, most times many light years wide, while the gasses inside it run in currents but have no deffinate shape. The brightest nebulas are Herbig Haro but the most simple. They are usually formed from jets of gas coming off of stars.
Diffuse nebula
Protostar
A protostar is a loose ball of gas that has a ring of clouds called the proplanetary disc. For the protostar to transform from a nebula it has to contract. As it contracts the density and the tempature of the star increases. This contracting goes on for millions of years until it has achieved to have the preasure due to gravity and the thermal energy become equal. An interesting thing about protostars is that they don't shine. When they finally achieve in being a main sequence star they finally get a shine.
Protostars
Main Sequence Star
The main sequence star is the most important to us. This stage in the stars life is where our sun is at this point in time. It creates perfect living conditions for here on earth so we can all survive with water and food. The lifespan of one of these stars depends on the mass and on how long the star took to form. Our star took 20 million years to form but is estimated to last for 10 billion years. While a star with half of our suns mass could last up to 80 billion years.
Sirius- Main sequence Star
Red Giant
The red giant star is only one of the paths a star can take. They can also be a red dwarf star and a white dwarf star. the red giant is formed because it runs out of fuel, making the star cool ,creating a shell around the outer edge of the star. It then reheats and expands to make the star even bigger then before. The reason the newly created star is red is because of weak radiation. The weak radiation causes the star to turn red at this time.
Red giant
Red Dwarf
The red dwarf star is actually one of the most common stars in the universe. Most of us think that because the sun is a main sequence star that those are the most common but they are mistaken. A red dwar star is usually less then half the mass of the sun. But there is a limit to how small they can get. There comes a point where if the star gets any smaller it would not be able to sustain nuclear fusion in there cores. While the sun and other main sequence stars run out of fuel much sooner then red dwarfs its because the red dwarf uses its fuel at a much smaller rate. It uses about 1/10,000th the amount that our sun does, so it last longer.
Red Dwarfs
White Dwarf
This is what our sun will be when it is in its last stage of life. The white dwarf is a very small very hot star. The have a diameter about the size of the earth which we now know is not very big. these stars usually last billions of years in the universe. When the white dwarf finally dies it leaves behind a planetary shell creating a planetary nebula.
White Dwarf
