Basic Parts of a Star
Parts of a Star
The basic parts of a star are the core, photosphere, chromosphere and corona. The core is in the center of the star, it makes energy for the star. The photosphere is like a cloud in the sky, it looks solid because you can't see through it but it's not, its just gases. The chromosphere is transparent gases and visible radiation. The density of these gases decrease as you get away from the photosphere. The corona is the outermost part. Usually you can not see the the corona because of the brightness of the star. The corona is very hot. Because of the high temperature most of the radiation from the corona is emitted in ultraviolet wavelenghts.
Energy Generation
Stars generate energy in their cores which is the hottest part of the star. If a star is not hot enough for thermonuclear fusion to take place then another way a star can generate is to take 4 hydrogen atoms and turn them into 1 helium atom, which causes huge release of energy which heats the stars gas. (this is what happens in a "H-bomb") The energy generation going on in the core forces energy out pushing the gases out but there is and inward force of gravity keeping the star together.
H-R Diagram
Fomalhaut H-R Diagram
This is the H-R Diagram showing where our sun and the star fomalhaut are on it. The H-R diagram shows the relationship between the stars absolute magnitude or luminosity vs. spectral types and temperature. Our sun and fomalhaut are similar so the are near each other on the diagram. They are both class A stars.
Fomalhaut is not Contracting or Expanding
Fomalhaut
Fomalhaut is in the main sequence so it has gotten a balance between the outward force of energy and the inward force of gravity. Fomalhaut is only about 100 to 300 million years old and is expected to have a life of 1 billion years.