Thermonuclear Evolution

The process of stellar evolution begins with the formation of the star. It starts as a cloud of gas and dust. This is critical because the chemicals and amount of stuff in the cloud will determine the entire life of the star it’ s creating. The density will increase because of its gravity and its spin will become more dramatic. Then little tornados (well tornado like things) will form in the cloud. These will eventually become star systems. All the material falling onto the tornado causes it to start to heat up drastically. Eventually it will get to a temperature and density to become a protostar. When the protostar has almost collapsed on itself it will reach it’s maximum temperature. At this stage the surface temperature is much greater than

If it is, it will push the outer layers of the protostar outward and make the core less dense, so it will extinguish the thermonuclear reactions. These are failed stars called brown dwarfs. They are very plentiful, but also very hard to detect. But sometimes, in the rare case, the density and core temperature will be high enough to uphold stable thermonuclear reactions. After that, the fusion energy will reach the surface and it will become a main sequence star. All a main sequence stars radiant energy is produced by hydrogen fusion, because they do not shrink very much over a long period of time. There are two very different types of hydrogen burning reactions that stellar core material can do. If the star has a mass of less than 1.8 x Sol, then it undergoes this fairly simple and straightforward nuclear reaction (Called the proton-proton chain). Step 1- two protons fuse together. Step 2- Another proton collides with the nucleus, forming a helium-3 nucleus. Step 3- another helium-3 nucleus combines with it and it forms regular helium. That takes about a million years to get this far. (Just wow, and we haven’t even got to the good stuff

It weighs about half of what the star did during its main sequence lifetime, yet it's smaller than Uranus or Neptune. It's hotter than the star was when it was on the main sequence, and gives off blackbody radiation just like a hot star would; yet it produces no energy of its own and glows simply because it hasn't cooled off yet. Its surface gravity can measure well over 100 000 times the surface gravity of the Earth. Its average density is over a ton to the cubic centimeter; it is so incredibly dense, in fact, that all the atoms that make it up are packed together as tightly as the laws of Fermion physics will allow, making it a totally incompressible "electron degenerate" gas. This oddball super-dense stellar remnant is called a white