An Etymological Dictionary of Astronomy and Astrophysics

A disk that would form around a star when the star injects matter into a close orbit. This is in contrast to an → accretion disk, which transfers matter from outside to the star. The mass gets injected into the decretion disk by a not yet well-known mechanism, most probably a combination of → non-radial pulsation, fast rotation, and possibly small-scale → magnetic fields. See also → viscous decretion disk.

See also: → decretion; → disk.