An Etymological Dictionary of Astronomy and Astrophysics

The region of a star in which the energy generated by → nuclear fusion in the core is transferred outward by → electromagnetic radiation and not by → convection. Such zones occur in the interior of
low-mass stars, like the Sun, and the envelopes of → massive star.
The radiative zone of the Sun starts at the edge of the core of the Sun, about 0.2 solar radii, and extends up to about 0.7 radii, just below the → convective zone.

See also: → radiative; → zone.