3 research outputs found
The solar photospheric abundance of carbon.Analysis of atomic carbon lines with the CO5BOLD solar model
The use of hydrodynamical simulations, the selection of atomic data, and the
computation of deviations from local thermodynamical equilibrium for the
analysis of the solar spectra have implied a downward revision of the solar
metallicity. We are in the process of using the latest simulations computed
with the CO5BOLD code to reassess the solar chemical composition. We determine
the solar photospheric carbon abundance by using a radiation-hydrodynamical
CO5BOLD model, and compute the departures from local thermodynamical
equilibrium by using the Kiel code. We measure equivalent widths of atomic CI
lines on high resolution, high signal-to-noise ratio solar atlases. Deviations
from local thermodynamic equilibrium are computed in 1D with the Kiel code. Our
recommended value for the solar carbon abundance, relies on 98 independent
measurements of observed lines and is A(C)=8.50+-0.06, the quoted error is the
sum of statistical and systematic error. Combined with our recent results for
the solar oxygen and nitrogen abundances this implies a solar metallicity of
Z=0.0154 and Z/X=0.0211. Our analysis implies a solar carbon abundance which is
about 0.1 dex higher than what was found in previous analysis based on
different 3D hydrodynamical computations. The difference is partly driven by
our equivalent width measurements (we measure, on average, larger equivalent
widths with respect to the other work based on a 3D model), in part it is
likely due to the different properties of the hydrodynamical simulations and
the spectrum synthesis code. The solar metallicity we obtain from the CO5BOLD
analyses is in slightly better agreement with the constraints of
helioseismology than the previous 3D abundance results. (Abridged)Comment: Astronomy and Astrophysics, accepte