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physical phenomena > process > physical process > nuclear process > pycnonuclear reaction

pycnonuclear reaction
subject			fact

pycnonuclear reaction	has temperature dependence weak
	has minimum temperature relatively low
	has definition Nuclear process that take place at relatively low temperatures and that are not strongly temperature-dependent.
	is a kind of nuclear process
physical process	has domain physics

Kinds of pycnonuclear reaction :

• proton-proton chain (4 kinds, 31 facts) (p-p chain) - thermonuclear reaction in which two protons collide a very high velocities and combine to form deuteurium, the deuteurium can capture a proton to form tritium and tritium can capture a proton to form helium, A series of thermonuclear reactions in which hydrogen nuclei are transformed into helium nuclei. The temperature and density required are about 10⁷ K and 100 g cm^-3. It is the main source of energy in the Sun, where 10³⁸ of these reactions occur every second. All parts of this reaction have been observed in the laboratory, except for the first step ¹H(p, β⁺v)²D, which occurs only a few times in 10¹² collisions of protons. But the first two reactions provide about one-third of the Sun's total energy release. The p-p chain divides into three main branches: PP I, PP II and PP III., Process of nuclear fusion by which relatively cooler stars produce and radiate energy; hotter stars commonly achieve the same result by means of the carbon-nitrogen cycle., The nuclear sequence by which the Sun and all other main-sequence stars with less than 1.5 solar masses fuse hydrogen into helium., An important nuclear fusion reaction that occurs in stars. It begins with the fusion of two hydrogen nuclei, each of which consists of a single proton.