An Etymological Dictionary of Astronomy and Astrophysics

The → nuclear reaction that occurs when an → atomic nucleus captures a → neutron. Neutron capture is the primary mechanism (principally, the → s-process and → r-process)
by which very massive nuclei are formed in stars and during → supernova explosions.
Instead of → fusion of similar nuclei, heavy, → neutron-capture elements are created by the addition of more and more neutrons to existing nuclei.

See also: → neutron; → capture.