Neutrinos Prove Our Sun Is Undergoing a Second Type of Fusion in Its Core - ScienceAlert

Much of our understanding of stellar fusion comes from theoretical models of atomic nuclei, but for our closest star, we also have another source: neutrinos created in the Sun's core.

Whenever atomic nuclei undergo fusion, they produce not only high energy gamma rays but also neutrinos.

This proved that nuclear fusion occurs in the Sun, but not the type of fusion.

We now know that the solar neutrinos detected from early experiments come not from the common pp-chain neutrinos, but from secondary reactions such as boron decay, which create higher energy neutrinos that are easier to detect.

Then in 2014, a team detected low-energy neutrinos directly produced by the pp-chain. Their observations confirmed that 99 percent of the Sun's energy is generated by proton-proton fusion.

The energy levels of various solar neutrinos.