Glossary term: Radiative Zone

Also known as radiative envelope

Description: Energy is set free by nuclear fusion reactions in the core of a star, and eventually radiated away into space from the star's surface. There are several ways that energy is transported from the star's core to the surface. The radiative zone, radiative region or radiation zone is the shell-shaped region within a star where the energy is transported outwards by means of radiation: with photons repeatedly scattering off nuclei and electrons, losing some energy in the process but also leading to the emission of new thermal-radiation photons. Due to frequent scattering, progress is slow; in our Sun, photons need almost 200,000 years to cross the radiative zone. The size of the radiative zone depends on a star's mass – below 0.3 solar masses, stars have no radiative zone at all.

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Term and definition status: This term and its definition is still awaiting approval

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