The photospheric solar oxygen project. I. Abundance analysis of atomic lines and influence of atmosp

By E. Caffau, H. Ludwig, M. Steffen, Thomas R. Ayres, P. Bonifacio, R. Cayrel, Bernd Freytag, B. Plez. 2008

209 citations recorded by the source corpus.

Context: The solar oxygen abundance has undergone a major downward revision in the past decade, the most noticeable one being the update including 3D hydrodynamical simulations to model the solar photosphere. Up to now, such an analysis has only been carried out by one group using one radiation-hydrodynamics code. Aims: We investigate the photospheric oxygen abundance considering lines from atomic transitions. We also consider the relationship between the solar model used and the resulting solar oxygen abundance, to understand whether the downward abundance revision is specifically related to 3D hydrodynamical effects. Methods: We performed a new determination of the solar photospheric oxygen abundance by analysing different high-resolution high signal-to-noise ratio atlases of the solar flux and disc-centre intensity, making use of the latest generation of CO5BOLD 3D solar model atmospheres. Results: We find 8.73 ? log (N_O/N_H) +12 ? 8.79. The lower and upper values represent extreme assumptions on the role of collisional excitation and ionisation by neutral hydrogen for the NLTE level populations of neutral oxygen. The error of our analysis is ± (0.04± 0.03) dex, the last being related to NLTE corrections, the first error to any other effect. The 3D ?granulation effects? do not play a decisive role in lowering the oxygen abundance. Conclusions: Our recommended value is log (N_O/N_H) = 8.76 ± 0.07, considering our present ignorance of the role of collisions with hydrogen atoms on the NLTE level populations of oxygen. The reasons for lower O abundances in the past are identified as (1) the lower equivalent widths adopted and (2) the choice of neglecting collisions with hydrogen atoms in the statistical equilibrium calculations for oxygen. This paper is dedicated to the memory of Hartmut Holweger.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2e6b13ae985a6cf5d94b1bc54fafc088815bc9d7

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Citations in the corpus

Solar Neutrinos: Status and Prospects (2012, unknown): “The solar abundance problem could have a pedestrian solution: the 3D analysis of Caffau et al. (2008, 2009, 2010) yielded abundances higher than the AGSS09 values, though this appears to be due to spectral line choices rather than photospheric model differences (Grevesse et al. 2011), a conclusion…”
A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres (2008, methodology): “…element abundance, as the most prominent example, has been revised downward to 0O = 8.66 ± 0.05 by Asplund et al. (2005) and to only 0O = 8.76 ± 0.07 by Caffau et al. (2008), both based on 3D hydrodynamical simulations of the solar photosphere in combination with non-LTE line transfer (see…”
THE ATOMIC-TO-MOLECULAR TRANSITION IN GALAXIES. II: H i AND H2 COLUMN DENSITIES (2008, methodology): “…this comparison, for convenience we first break the sample into four metallicity bins: −1.25 < logZ ′ < −0.5, −0.5 < logZ ′ < −0.25, −0.25 < logZ ′ < 0, and 0 < logZ ′ < 0.5, where Z ′ = Z/Z⊙ and we adopt log(O/H) + 12 = 8.76 as the value corresponding to solar metallicity (Caffau et al. 2008).”
Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes (2016, background): “While this “Solar Oxygen Crisis” now appears to be largely resolved (e.g., Caffau et al. 2008), this example demonstrates how even our nearest star, for which we have the most information and which we use as an anchor point for essentially all of our stellar evolutionary models, can still have…”
The chemical composition of the Sun (2009, methodology): “Both Caffau et al. (2008a) and Asplund et al. (2009c) found that this line returns a slightly higher abundance than the 630 nm line, but still consistent within the uncertainties.”
Improving PARSEC models for very low mass stars (2014, background): “2.1 by Alan W. Irwin 1; • revised opacities from AESOPUS (Marigo & Aringer 2009)2 and the OPAL group (Iglesias & Rogers 1996)3; • adoption of the revised Caffau et al. (2008, 2009) solar chemical abundances; • extended nuclear networks and the reaction rates recommended in the updated JINA REACLIB…”
First stars XII. Abundances in extremely metal-poor turnoff stars,and comparison with the giants (2009, background): “…in the past (Asplund et al. 2004) are not due to the use of 3D hydrodynamical models, but to low measured EWs and extreme assumptions on the role of collisions with H atoms in the NLTE computations (see Caffau et al. 2008, for a discussion and a new measurement of the solar oxygen abundance).”
Scaled solar tracks and isochrones in a large region of the Z-Y plane. II. From 2.5 to 20 solar masses (2009, unknown): “Some more recent studies (e.g., Caffau et al. 2008, and references therein) confirm the high O abundances typical of older compilations of solar abundances, rather than the low values claimed by Asplund et al.(2004).”
Accurate fundamental parameters for 23 bright solar-type stars (2010, background): “However, recent studies of the metallicity of the Sun indicate a lower value than previously thought (mostly due to revision of the light elements C and O; Caffau et al. 2008).”
Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere (2010, methodology): “For details of the analysis see Caffau et al. (2008a) and Caffau and Ludwig (2008).”
The star formation history and accretion-disc fraction among the K-type members of the Scorpius–Centaurus OB association (2016, methodology): “The PARSEC models adopt the Caffau et al. (2008, 2009) solar abundances with a initial He fraction of Y=0.284, whereas the Exeter/Lyon models use the Caffau et al. (2011) solar abundances, Y=0.271.”
The FIP and Inverse FIP Effects in Solar and Stellar Coronae (2015, methodology): “…of subsequent papers analyzing other allowed and forbidden lines in O I, and also molecular OH supported this change (Asplund et al., 2004, 2005a; Meléndez, 2004; Socas-Navarro and Norton, 2007; Meléndez and Asplund, 2008), though Ayres (2008) and Caffau et al. (2008) offered more cautious views.”