000002126 001__ 2126
000002126 005__ 20160706150324.0
000002126 0247_ $$2DOI$$a10.1051/0004-6361/201424109
000002126 037__ $$aASTROimport-283
000002126 100__ $$aScott, P.
000002126 245__ $$aThe elemental composition of the Sun. I. The intermediate mass elements Na to Ca
000002126 260__ $$c2015
000002126 520__ $$aThe chemical composition of the Sun is an essential piece of reference data for astronomy, cosmology, astroparticle, space and geo-physics: elemental abundances of essentially all astronomical objects are referenced to the solar composition, and basically every process involving the Sun depends on its composition. This article, dealing with the intermediate-mass elements Na to Ca, is the first in a series describing the comprehensive re-determination of the solar composition. In this series we severely scrutinise all ingredients of the analysis across all elements, to obtain the most accurate, homogeneous and reliable results possible. We employ a highly realistic 3D hydrodynamic model of the solar photosphere, which has successfully passed an arsenal of observational diagnostics. For comparison, and to quantify remaining systematic errors, we repeat the analysis using three different 1D hydrostatic model atmospheres (marcs, miss and Holweger  Müller 1974, Sol. Phys., 39, 19) and a horizontally and temporally-averaged version of the 3D model (? 3D ?). We account for departures from local thermodynamic equilibrium (LTE) wherever possible. We have scoured the literature for the best possible input data, carefully assessing transition probabilities, hyperfine splitting, partition functions and other data for inclusion in the analysis. We have put the lines we use through a very stringent quality check in terms of their observed profiles and atomic data, and discarded all that we suspect to be blended. Our final recommended 3D+NLTE abundances are: log ɛNa = 6.21 ± 0.04, log ɛMg = 7.59 ± 0.04, log ɛAl = 6.43 ± 0.04, log ɛSi = 7.51 ± 0.03, log ɛP = 5.41 ± 0.03, log ɛS = 7.13 ± 0.03, log ɛK = 5.04 ± 0.05 and log ɛCa = 6.32 ± 0.03. The uncertainties include both statistical and systematic errors. Our results are systematically smaller than most previous ones with the 1D semi-empirical Holweger  Müller model, whereas the ⟨ 3D ⟩ model returns abundances very similar to the full 3D calculations. This analysis provides a complete description and a slight update of the results presented in Asplund et al. (2009, ARA, 47, 481) for Na to Ca, and includes full details of all lines and input data used. Tables 1-4 and Appendix A are available in electronic form at http://www.aanda.org
000002126 700__ $$aGrevesse, N.
000002126 700__ $$aAsplund, M.
000002126 700__ $$aSauval, A. J.
000002126 700__ $$aLind, K.
000002126 700__ $$aTakeda, Y.
000002126 700__ $$aCollet, R.
000002126 700__ $$aTrampedach, R.
000002126 700__ $$aHayek, W.
000002126 773__ $$cA25$$pAstronomy and Astrophysics$$v573$$y2015
000002126 85642 $$ahttp://esoads.eso.org/abs/2015A%26A...573A..25S
000002126 905__ $$apublished in
000002126 980__ $$aREFERD