For some time there is a controversy about the Neon abundance,
this article explains the problem.
Abstract:
Quote:
The standard solar model was so reliable that it could predict the existence of the massive neutrino. Helioseismology measurements were so precise that they could determine the depth of the convection zone. This agreement between theory and observation was the envy of all astrophysics – until recently when sophisticated three-dimensional hydrodynamic calculations of the solar atmosphere reduced the metal content by a factor of almost two. Antia & Basu (2005) suggested that a higher value of the solar neon abundance, ANe /AO = 0.52, would resolve this controversy. Drake & Testa (2005) presented strong evidence in favor
of this idea from a sample of 21 Chandra stars with enhanced values of the neon abundance, ANe /AO = 0.41. In this paper, we have analyzed solar active region spectra from the archive of the Flat Crystal Spectrometer on Solar Maximum Mission, a NASA mission from the 1980s, as well as full-Sun spectra from the pioneering days of X-ray astronomy in the 1960s. These data seem consistent with the standard neon-to-oxygen abundance value, ANe /AO = 0.15 (Grevesse & Sauval 1998). If these results prove to be correct, than the enhanced-neon hypothesis will not resolve the current controversy.
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This is corroborated in
this article
Quote:
Aims. To determine the neon-to-oxygen abundance in the quiet Sun, a proxy for the photosphericabundance ratio.
Methods. An emission measure method applied to extreme ultraviolet emission lines of Ne iv–vi and O iii–v ions observed by the Coronal Diagnostic Spectrometer on the SOHO satellite.
Results. The average Ne/O abundance ratio in supergranule cell centre regions is 0.18 ± 0.05, while in supergranule network regions is 0.16 ± 0.04. A photospheric Ne/O ratio of 0.17 ± 0.05 is suggested, in good agreement with the most recent compilation of solar photospheric abundances, but discrepant with a recent Ne/O ratio derived from stellar X-ray spectra and revised neon abundances suggested from solar interior models.
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Could you explain what these findings mean for the solar model? Personally I don't really trust numbers derived from "solar interior models", but even so any model should be consistent with observations.
Cheers.