Life Cycle of Stars
A star’s life cycle is determined by its mass. The larger its mass, the shorter the life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas from which it was born. There are 3 different courses that the star goes through depending on their size. Each star begins as a Nebula, after they go through this stage they form into a Protostar, hydrogen undergoes nuclear fusion to form helium and the star begins to form. The star now either becomes a small star, a normal sized star or a very large star. If the star is a very large star then the hydrogen is quickly used up by nuclear fusion. The core contracts while the outer layers expand. The surface temperature decreases and this whole process occurs quickly. It then turns into a Super Giant, helium and carbon are used up by nuclear fusion. A Super Nova is then formed; this is when the outer layers are blown off in a large violent explosion. The core material contracts and the remains are more than 1.44 times the size of our Sun. After this the star then forms into a Pulsar. This is where material adjusts due to gravity, and discharges X-ray. If the stars mass is less than 3 solar masses, it becomes a Neutron Star. If the mass is more than 3 solar masses it becomes a Black Hole and if the star either turns into a Neutron Star or a Black Hole it is the end of a very large stars life cycle.
A normal sized star goes through a different cycle than a very large star. Once the star is formed into a normal sized star the hydrogen will be used up by the nuclear fusion. The core contracts while the outer layers expand. The surface temperature decreases and all of this occurs slowly. Once this process is completed it turns into a Red Giant, this is when helium and carbon are used up by nuclear fusion. Then it turns into a Nova where the outer layers are blown off in a large violent explosion. The core material contracts and the remains are less than 1.44 times the size of our Sun. The star then turns into a White Dwarf and the last stage a normal sized star goes through is turning into a Black Dwarf.
A small star goes through the same life cycle as a normal star. The only difference is that a normal star turns into a Giant Red while a small star turns into a Red. The is because a small star is smaller than a normal sized star so it won’t become a giant.
A normal sized star goes through a different cycle than a very large star. Once the star is formed into a normal sized star the hydrogen will be used up by the nuclear fusion. The core contracts while the outer layers expand. The surface temperature decreases and all of this occurs slowly. Once this process is completed it turns into a Red Giant, this is when helium and carbon are used up by nuclear fusion. Then it turns into a Nova where the outer layers are blown off in a large violent explosion. The core material contracts and the remains are less than 1.44 times the size of our Sun. The star then turns into a White Dwarf and the last stage a normal sized star goes through is turning into a Black Dwarf.
A small star goes through the same life cycle as a normal star. The only difference is that a normal star turns into a Giant Red while a small star turns into a Red. The is because a small star is smaller than a normal sized star so it won’t become a giant.
Red Giant
The Red Giants produce a large amount of light because of their great size. All normal stars are expected to pass through the Red Giant phase at some time in their lifetime. It is usually 10-1500 times the size of our Sun’s current size. Most Red Giants are red but some of them are orange or even yellow because of the amount of different chemicals or elements inside. The Red Giant phase first starts with the helium from the star beginning to burn. To give off the energy produced by the helium burning, the star expands into a Red Giant. As a Red Giant burns through its helium supply and increases its core mass, it begins to collapse itself. When this happens the next stage of the stars life cycle begins.
H/R Diagram
Here is a diagram of the stars and the temperature of them.