Polaris is a very incredible star. It is also known as the north star. It has been a part of many stories and events. Polaris was not always the north star and will not always be the north star. No one knows when Polaris was born but we do know that the star formed like any other star. It was just a tiny speck that the started to take materials from around it. It then started to grow and is now about 46 times the mass of our sun. It is also the 50th brightest star in the galaxy. People think that its the number one most brightest but that is incorrect.
Stars Contract or Expand when they are pulling or pushing material away or to the core. Our star does not do this because it already is done forming. Stars only expand and contract when they are forming or dying.
During most of a stars life it is called a Main Sequence star.
There are a bunch of different parts to a star. To start off, let me explain how a star works. Stars are formed when they pull a bunch of material and dust particles together to create a protostar. The star then begins growing and gets hotter and hotter. It burns through gasses, and when the gasses finally run out, the star collapses in on itself.
The Central Core, Convective and Radiative zones, the Photosphere, the Chromosphere, and the Corona are all parts of a star. The Core is where nuclear fusion occurs to power the star. The Convective and Radiative zone allow the energy or power to be transferred through the star. In the Convection zone the hot air moves around like a hair dryer. In the Radiative zone the heat is transferred like a light bulb. Now to the cool part. The part of the star that we see, visible light, is the Photosphere or the surface of the star. Just after the Photosphere is the Chromosphere. It is the thin layer that looks red. It looks red because it has a tremendous amount of hydrogen in it. The Corona is just like a atomsphere.
As you can see the arrows represent the direction that the air moves around in the star. The air moves a lot like the heat in a hair dryer. That is how the heat and energy travels through the star.