Solar Observations in Bulgaria

The core makes about 2% of the Sun’s volume (core’s radius is ~1/4 Rסּ) but contains nearly half of its mass. The highest temperature is in the center ~1.55x10⁷ and decreases outwards to 9.42x10⁶ K. The high temperatures and densities provide conditions for the nuclear fusions that power the Sun. Most energy is provided from the three step process of hydrogen to helium conversion (proton-proton chain). A single proton-proton chain yields 26.73 MeV in gamma rays and ~0.5 MeV in two neutrinos.