What is Stellar Nucleosynthesis?
Stellar nucleosynthesis is the process by which the natural abundances of the chemical elements within stars change due to nuclear fusion reactions in the cores and overlying mantles of stars.
Stellar nucleosynthesis is the process by which elements are created within stars by combining the protons and neutrons together from the nuclei of lighter elements. This is not the only form of nucleosynthesis, however, but usually, when scientists talk about nucleosynthesis, it's shorthand for stellar nucleosynthesis.
For a real deep understanding of the topic, you can visit :
You could also watch a video by Lawrence Krauss on Cosmic Connections