Hi, i'm Evan, I started out as a nebula which is a giant cloud of gas and dust and the temperature gets cold so molecules start to form and I became a protostar.
Eventually, i will reach my hydrostatic equilibrium, in which my gravity compression is balanced by my outward pressure, giving myself a solid shape. I then become a main sequence star. I will spend 90 percent of my life in this stage, fusing hydrogen molecules and forming helium in my core. The sun of our solar system is currently in its main sequence phase.
Once all of the hydrogen in my core is converted to helium, my core collapses on itself, causing myself to expand. As i expand, i first becomes a sub-giant star, then a red giant. Red giants have cooler surfaces than main sequence stars; and because of this, they will appear red rather than yellow. I'm star is massive enough, i can become large enough to be classified as a supergiant.