The structure of a solar-like star and a red giant. The two images are not to scale - the scale is given in the lower right corner. It iscommon to divide the Sun's (and solar-like stars') interior into threedistinct zones: The uppermost is the Convective Zone. It extends downwards from the bottom of the photosphere to a depth of about 15% ofthe radius of the Sun. Here the energy is mainly transported upwards by(convection) streams of gas. The Radiative Zone is below the convectionzone and extends downwards to the core. Here energy is transportedoutwards by radiation and not by convection. From the top of this zoneto the bottom, the density increases 100 times.The core occupies the central region and its diameter is about 15% ofthat of the entire star. Here the energy is produced by fusionprocesses through which hydrogen nuclei are fused together to producehelium nuclei. In the Sun, the temperature is around 14 milliondegrees. In red giants, the convection zone is much larger, encompassing morethan 35 times more mass than in the Sun.
Photoshop and Cinema 4D.