As long as this is the primary thing a star is doing, it’s considered to be on the main sequence ... Now known as the ...

leading to a state of equilibrium between gravitational collapse and the energy released during fusion Key fact In a main sequence star, hydrogen nuclei fuse together to form helium nuclei.

More massive stars than the Sun have a very different life cycle and follow the right hand path in the diagram above: \({Nebula}\rightarrow{protostar}\rightarrow{main~sequence~star}\rightarrow{red ...