Stars are a huge balls of hot gas and some of them are very shine and some of them are very dim. Stars can't live with out gases. They also have differents colors and sizes.
Actually the stars you see at night looks like they are very small but apparently they are even bigger and brither than the Sun. Stars also can be classified in differents categories, which are colors, sizes, ages, luminosity, temperatures and spectral class.
Types of Stars
There are four types of stars. Which are Super Giant, Giants, White Dwarf & Main Sequence. Supergiant stars are in a huge middle age stars that could have any temperature, color, brightness and spectral class. Giant stars are in middle age and they are large and shine. White Dwarf they are white old and small stars. They have very law temperature and mostly they are hot stars and dim stars. Main Sequence are young medium stars that have middle age and they can be any colors, sizes, ages, luminosity, temperatures and spectral class. They also are bright and dim stars.
H-R Diagram
H-R Diagram which stands for Hertzsprung-Russel Diagram. H-R Diagram is a graphical tool that use to classify stars by their luminosity, spectral type, color, temperature and their stages.
In this diagram also shows the stars names, their sizes, their relationships and the differences between them. With all those informations you can find their spectral class.
Nuclear Fusion
Nuclear Fusion is when two hydrogen molecules gets together and makes one helium molecule. This is a process that which the stars make their energies and their heat.
The Life Cycle of a Star
First of all, all the stars are born in a giant clounds od dust and gas called Stellar Nebula. There are three differents types of stars, which are Sun-like Stars, Huge Stars and Giant Stars.
Sun-like stars, begin with Stellar Nebula and then goes through Red Giants, Planetary Nebula, White Dwarf, and Black Dwarf. Huge stars, starts with Stellar Nebula too and then become a Red Giant star, and after that explodes into Supernova and then become a Neutron Star. Giant Stars also starts with Nebula Stellar, then goes through Red Super Giant, after that exploudes in to Supernova and finally become a Black Dwarf.
