Glossary term: Convective Zone

Also known as convective envelope

Description: The convective zone is a region in a star where convection, rather than radiation is the main method of heat transportation. Convection requires a large difference of temperatures along a given region. When radiation is inefficient, convection sets in.

In the convective zone, hot material deeper in the star rises up to cooler regions where it cools and then sinks back down. In the most massive main sequence stars the stellar core is convective while the outer layers are radiative. In main sequence stars similar to the Sun, the region below the atmosphere is convective while the region deeper than this is radiative. In the lowest mass stars, the entire star, from the core to just below the atmosphere, is convective.

Convective motions result in large scale mixing of chemical elements. When convection reaches the surface of a star, it can transport freshly synthesized elements and isotopes to the surface, which leaves an imprint in the spectra recorded by astronomers.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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