(Description) Figure 4 An artist’s drawing of the internal structure of the Sun, showing surface features and internal layers. As you shall see in Section 3, the core of the Sun is at a very high temperature and pressure, sufficient to sustain the nuclear reactions that power its energy output. (NASA)

Week 5: The Sun and the stars

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A cutaway drawing showing the surface and the inner layers of the Sun. The innermost layers are depicted in false colour, and labelled as the inner core, surrounded by the radiative zone, and then further out, the convective zone. The photosphere forming the visible surface of the Sun is illustrated as a thin layer of orange and red granulations with sunspots. Subsurface flows are labelled just below the photosphere. Above the photosphere are the chromosphere, a thin shell of hot gas, and above that the corona, depicted as red steamers radiating out into space.

2.3 The mass, composition and structure of the Sun