An Etymological Dictionary of Astronomy and Astrophysics

The fusion of a deuterium nucleus with a proton which produces the lightest isotope of helium: D + H → ³He + γ. Deuterium burning occurs in stellar cores at a temperature exceeding
10⁶ K. The onset of deuterium burning marks the end of the → protostellar collapse. It is the only → nuclear reaction that occurs in → brown dwarfs. In normal stars, it is the second step in the → proton-proton chain which leads to the formation of ⁴He, allowing stars to arrive on the → main sequence.

See also: → deuterium; → burning.