| Term: | Solar photosphere |
| Definition: |
The visible surface of the Sun (temperature 5700 K), just below the chromosphere and just above the convective zone. The solar photosphere is a thin layer of roughly 300 km wide. Its temperature decreases uniformly with height, from about 6,600 K (pressure 0.868 millibars) at its bottom, to about 4,400 K (pressure 125 mb), where it merges with the chromosphere. The photosphere has a 'rice-grain' appearance, called granulation, caused by rising (hot) and falling (cool) material in the convective cells just below the photosphere. Other main features of the photosphere are sunspots, faculae, and supergranulation. |