Click HERE to see the website we made this HR diagram on!
The red x is the star Arcturus.
Basic Parts of a Star
Parts of a star
The core of a star is beneath the photospehere of a star. The photosphere is the part of the star that we often mistake for the surface of the star. The surface of the star is actually the chromosphere. Since there is hydrogen in the chromosphere, we often see it as being red. Then comes the corona. Composed of sheer gas, it is in the atmosphere holding very high temperatures.
How Energy Moves Within a Star
The heat in the star first starts in the core. It is then emitted to the surface where it then cools and is pulled back into the core. This is happening all the time on a infinite circuit.
Where Stars Generate Energy
Energy is generated by Nuclear Fusion in the core of the star, which is explained on the Birth page (Located at the top of the page). In this process, Nuclear Fusion creates a lot of energy and gives it off, well wait... How does it move through the star? you may ask. The energy is created in the core of the star after Nuclear Fusion takes place, then it moves through the star and gives off immense amounts of energy and helium. This process repeats itself until death.
Why It Doesn't Expand and Contract
Arcturus doesn't expand and contract in this sequence of it's life because the energy (outward force) and the gravity (inward force) are equal and stable. The amount of gravity that pushes down on Arcturus is equalized by the amount of energy given out by Arcturus.