Vol. 577
In section 9. The Sun

The solar oxygen abundance from an empirical three-dimensional model

The oxygen abundance in the solar photosphere, and consequently the solar metallicity itself, is still a controversial issue with far-reaching implications in many areas of Astrophysics. This paper presents a new determination obtained by fitting the forbidden O I line at 6300 Å for the first time with an observational 3D model. The resulting best-fit abundance is log E(O)=8.90. However, by introducing minor tweaks in the model and the procedure, it is possible to retrieve very different values, even down to log E(O)=8.70. This extreme sensitivity of the abundance to possible systematic effects is not specific to this particular work, but probably reflects the real uncertainty inherent to all abundance determinations that are based on a prescribed model atmosphere.