Proton—proton chain There is a series of reactions. First, deuterium (2H) is formed. from the collision of two protons.
{"Image DocumentName": "Proton\u2014proton chainThere is a series of reactions. First, deuterium (2H) is formed. from the collision of two protons.", "Image ImageDescription": "1a) p + p \uf0ae 2H + e+ + \uf06ee with Q = MeV, E\uf06e < MeV. Alternatively, the p\u2014e\u2014p reaction can start the chain: 1b) p + e- + p \uf0ae 2H + \uf06ee with Q = 0.4 MeV, E\uf06e =1.442 MeV. where Q is the amount of energy produced (e.g. in \uf067-ray photons, positron annihilation, and particle kinetic energy) which is available for heating the Sun (i.e. to produce its luminosity); E\u03bd is the neutrino energy (neutrinos escape from the Sun and so carry away this energy). Both reactions proceed very slowly \u2013 first, 2 protons must penetrate each other to within 1.7 x m (only ~10-8 of them do), secondly, one must undergo an inverse \u03b2 decay during the collision process: p \u2192 n + e+ + \u03bde.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}