Structure of the Solar Photosphere

The majority of measured solar abundances refer to the solar photosphere. In general, when determining photospheric abundances a plane-parallel atmosphere and LTE are assumed. However, the photosphere is structured by granulation, magnetic fields and p-modes. They change line profiles by the thermal inhomogeneities and wavelength shifts they introduce. A brief description of the first two of these phenomena is given and some of the ways in which they influence abundances are pointed out. Departures from LTE also occur. The magnitude of the errors introduced into elemental abundances by neglecting such departures is also briefly discussed.