Line formation in solar granulation III .

Using realistic hydrodynamical simulations of the solar surface convection as 3D, time-dependent, inhomoge-neous model atmospheres, the solar photospheric Si abundance has been determined to be log ǫ Si = 7.51 ± 0.04. This constitutes a difference of 0.04 dex compared with previous estimates based on the 1D Holweger-Müller (1974) model, of which half is attributable to the adopted model atmosphere and the remaining part to the improved quantum mechanical broadening treatment. As a consequence, all meteoritic abundances should be adjusted downwards by the same amount. In particular the me-teoritic Fe abundance will be log ǫ Fe = 7.46 ± 0.01, in good agreement with the recently determined photospheric Fe abundance (Asplund et al. 2000b). The existing uncertainties unfortunately prevent an observational confirmation of the postulated effects of elemental migration of metals in the Sun.