Radiation zone

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An illustration of the structure of the Sun
 · Granules
 · Sunspot
 · Photosphere
 · Chromosphere
 · Convection zone
 · Radiation zone
 · Tachocline
 · Solar core
 · Corona
 · Flare
 · Prominence
 · Solar wind

A radiation zone, radiative zone or radiative region is a layer of a star's interior where energy is primarily transported toward the exterior by means of radiative diffusion and thermal conduction, rather than by convection.[1] Energy travels through the radiation zone in the form of electromagnetic radiation as photons.




Main sequence stars[edit]

For main sequence stars—those stars that are generating energy through the thermonuclear fusion of hydrogen at the core, the presence and location of radiative regions depends on the star's mass. Main sequence stars below about 0.3 solar masses are entirely convective, meaning they do not have a radiative zone. From 0.3 to 1.2 solar masses, the region around the stellar core is a radiation zone, separated from the overlying convection zone by the tachocline. The radius of the radiative zone increases monotonically with mass, with stars around 1.2 solar masses being almost entirely radiative. Above 1.2 solar masses, the core region becomes a convection zone and the overlying region is a radiation zone, with the amount of mass within the convective zone increasing with the mass of the star.[4]

The Sun[edit]

In the Sun, the region between the solar core at 0.2 of the Sun's radius and the outer convection zone at 0.71 of the Sun's radius is referred to as the radiation zone, although the core is also a radiative region.[1] The convection zone and the radiation zone are divided by the tachocline, another part of the Sun.

Notes and references[edit]

  1. ^ a b c Ryan, Sean G.; Norton, Andrew J. (2010), Stellar Evolution and Nucleosynthesis, Cambridge University Press, p. 19, ISBN 0-521-19609-4 
  2. ^ Elkins-Tanton, Linda T. (2006), The Sun, Mercury, and Venus, Infobase Publishing, p. 24, ISBN 0-8160-5193-3 
  3. ^ LeBlanc, Francis (2010), An Introduction to Stellar Astrophysics (1st ed.), John Wiley and Sons, p. 168, ISBN 1-119-96497-0 
  4. ^ Padmanabhan, Thanu (2001), Theoretical Astrophysics: Stars and stellar systems, Theoretical Astrophysics, 2, Cambridge University Press, p. 80, ISBN 0-521-56631-2 

External links[edit]