Birth Phase of Fomalhaut
Protostar
Like most main sequence stars Fomalhaut more than likely started out as a Stellar Nursery which is a large collection of dust and other particles that have been scattered throughout the universe and ended up together. The dust particles ended up clustering together, once they began to cluster together they increased in size and their gravitational pull increase which in turn brought in more particles which in turn increased gravity, this cycle went on until a protostar was formed.
Nuclear Fusion
Nuclear Fusion Process
Nuclear fusion is when 2 or more nuclei fuse to form a single heavier nucleus. It is accompanied by the release or absorption of lots of energy. Thermonuclear fusion is many nuclei fusing at once, this has to have very high temperatures and densities. Nuclear fusion happens naturally in all active stars. Within stars, the nuclei tend to move around really fast until they reach such high speeds that once they collide they end up exploding, releasing massive amounts of energy and fusing together.