proton-proton chain

American  

[proh-ton-proh-ton] / ˈproʊ tɒnˈproʊ tɒn /

noun

Physics, Astronomy.

1. a series of thermonuclear reactions, responsible for the energy production in stars like the sun, in which the nuclei of hydrogen atoms are transformed into helium nuclei by sequential addition of single hydrogen nuclei.

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proton-proton chain Scientific  

1. A set of thermonuclear reactions in which hydrogen nuclei (protons) fuse to form deuterium; these then fuse to form light helium isotopes, releasing more hydrogen nuclei that undergo further fusion with each other and with other nuclei. The main product of the proton-proton chain is He 4, the most common isotope of helium. The proton-proton chain releases large amounts of energy and involves the conversion of protons into neutrons, positrons, and electron neutrinos. The proton-proton chain is the main reaction in most main-sequence stars, including the Sun.

2. See also carbon cycle triple alpha process

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Example Sentences

The series of reactions required to convert hydrogen to helium is called the proton-proton chain.

From Textbooks • Oct. 13, 2016

This is the second step of the proton-proton chain, the fusion reaction that converts hydrogen into helium in the Sun.

From Textbooks • Oct. 13, 2016

In the proton-proton chain, protons collide directly with other protons to form helium nuclei.

From Textbooks • Oct. 13, 2016

Therefore, the outcome is the same as in the proton-proton chain: four hydrogen atoms disappear, and in their place, a single helium atom is created.

From Textbooks • Oct. 13, 2016

What conditions are required before proton-proton chain fusion can start in the Sun?

From Textbooks • Oct. 13, 2016