A Reappraisal of the Solar Photospheric C/O Ratio

By C. Allende Prieto, D. Lambert, Martin Asplund. 2002

359 citations recorded by the source corpus.

An accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local thermodynamical equilibrium (LTE). We argue that the forbidden C I line at 8727 Å is largely immune to departures from LTE and can be realistically modeled using LTE radiative transfer in a time-dependent three-dimensional simulation of solar surface convection. We analyze the [C I] line in the solar flux spectrum to derive the abundance log ϵ(C) = 8.39 ± 0.04 dex. Combining this result with our parallel analysis of [O I] λ6300, we find C/O = 0.50 ± 0.07, in agreement with the ratios measured in the solar corona from gamma-ray spectroscopy and solar energetic particles.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/087b14d0ae2dd37f07d5f77cbd12f926b74db735

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In Astronomy and Astrophysics

1. P. Hopkins
2. R. Dav'e
3. A. Shapley
4. M. Pettini
5. L. Hernquist
6. C. Steidel
7. Martin Asplund
8. C. Conroy

In Atmospheric Science

1. K. Lodders
2. M. Marley
3. A. Showman
4. Adam Burrows
5. S. Basu
6. Martin Asplund
7. A. Meiksin
8. N. Grevesse

Citations in the corpus

• Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements (2003, background): “Recently, Holweger (2001), Allende Prieto et al. (2001, 2002) published a “new” determination of photospheric solar abundances, in particular for carbon and oxygen.”
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations (2009, methodology): “This abundance set (see Table 1) combines the abundances of Allende Prieto et al. (2001, 2002) for C and O, Holweger (2001) for N, Ne, Mg, Si, and Fe, and assumes nHe/nH = 0.1 which is a typical value for nebular with near-solar compositions.”
• S4N: A spectroscopic survey of stars in the solar neighborhood: The nearest 15 pc (2004, background): “Curiously, the most metal-rich stars are mainly dwarfs and subgiants with spectral types F or later (e.g. Feltzing et al. 2001; Allende Prieto 2002b; Taylor 2002).”
• Dynamics and Disequilibrium Carbon Chemistry in Hot Jupiter Atmospheres, with Application to HD 209458b (2006, background): “REFERENCES Ackerman, A. S., & Marley, M. S. 2001, ApJ, 556, 872 Allende Prieto, C., Lambert, D. L., & Asplund, M. 2001, ApJ, 556, L63 —.”
• Solar System Abundances and Condensation Temperatures of the Elements (2003, methodology): “The C/O ratio from the determination by Allende Prieto et al. (2001, 2002) is 0.5, which is slightly higher than the C/O ratio of 0.49 found by Grevesse & Sauval (1998), and clearly higher than 0.42 from Anders & Grevesse (1989).”
• Aluminum-, Calcium- and Titanium-rich Oxide Stardust in Ordinary Chondrite Meteorites (2008, methodology): “…calculations use the solar (and appropriately scaled solar for lowmetallicity) C and O abundances fromAnders & Grevesse (1989), whereas the postprocessing nucleosynthesis code uses the more recent and significantly lower solar abundances of these elements fromAllende Prieto et al. (2001, 2002).”
• Isotopic Compositions of Strontium, Zirconium, Molybdenum, and Barium in Single Presolar SiC Grains and Asymptotic Giant Branch Stars (2003, background): “Allende Prieto, Lambert, & Asplund (2002) have recently reevaluated the C/O ratio of the Sun based on a new photospheric measurement of the carbon abundance and the recent photospheric measurement of the oxygen abundance of Allende Prieto, Lambert, & Asplund (2001) and give a value of C”
• Abundances in a Large Sample of Stars in M3 and M13 (2004, background): “Allende Prieto et al. (2002), Asplund (2003), and Asplund et al. (2004) being considerably ( 0.2 dex) lower than those of Anders & Grevesse (1989) and somewhat lower than those of Grevesse & Sauval (1998).”
• The physics of the intergalactic medium (2007, methodology): “Updated solar abundances useful for modeling the abundances of the metal absorption systems are provided by Grevesse and Sauval (1998), Holweger (2001), Allende Prieto et al. (2001, 2002) and Asplund (2003).”
• Evidence for Solar Metallicities in Massive Star-forming Galaxies at z ≳ 2 (2004, background): “All of the galaxies for which we detected [N ii] have (O/H) abundances consistent with the most recent estimates of the solar abundance, 12þ log (O=H) ¼ 8:66 0:05, and that of the Orion Nebula, 12þ log (O=H)Orion ¼ 8:64 0:06 (Allende Prieto et al. 2002; Asplund et al. 2004; Esteban et al. 1998).”