The Sun
Sol · G2V main sequence · 10 direct HARPS S1D spectra · ESO 1102.D-0954(A) · PI: Dumusque · SNR 306–309
Section 01
General Information
A(Fe)☉ = 7.46 · C/O☉ = 0.55 · Asplund et al. (2021)
Section 02
NASA Interactive Visualization
Section 02
Our Findings
The Sun is not a target — it is the ruler. Every abundance in the Codex is expressed as [X/H] = A(X)★ − A(X)☉, which means getting the solar reference right is the single most important calibration decision in the pipeline. We use 10 direct HARPS S1D exposures (ESO 1102.D-0954(A), PI: Dumusque) — a direct solar feed, not asteroid-reflected sunlight — with SNR 306–309 per exposure.
Solar Calibration Results
A(X)_ours − A(X)_Asplund2021 for 15 measurable elements. Fe I recovers 0.00 dex by construction — the calibration anchor. Many elements show large systematic offsets driven by nonlinear line exclusions; these are actively under investigation before science targets are touched.
⚠ = hard_warning flag (systematic offset or high nonlinear fraction). Error bars = σ_total (stat ⊕ sys). Elements not shown (Ba, Co, Eu, K, Li, N, Na, O, Sc): not yet measurable with current optical HARPS coverage.
Alpha Elements [X/Fe]
[X/Fe] = δ(X) − δ(Fe). Reference line: 0.0 dex.
C/O Ratio
// C/O STATUS //
C/O cannot be computed until O I is recovered. The [O I] 6300.304 Å line requires Ni blend subtraction; Li I 6707 Å requires CN deblending. Both are in active development.
Problem Lines — Active Development
[O I] 6300.304 Å — Ni I Blend
The forbidden oxygen line at 6300.304 Å is blended with Ni I at 6300.336 Å (Δλ = 0.032 Å). At HARPS resolution (R~115,000) they are marginally resolved but the Ni contribution must be computed from the measured Ni abundance and subtracted analytically. Until Ni is cleanly measured in the solar calibration run, this blend correction propagates uncertainty into C/O. Currently: O I has no usable lines returned by the pipeline.
Li I 6707.76 Å — CN Blend
The lithium doublet at 6707.76 + 6707.91 Å is contaminated by CN molecular lines in cool, metal-rich stars. In the Sun this is a minor issue, but in 55 Cancri A ([Fe/H] = +0.32) CN blending becomes significant. The pipeline currently flags all Li I measurements in the solar run as nonlinear-excluded. Accurate Li requires an updated CN linelist and deblending step — planned for Milestone B.
⬇ Download Raw EW Data (CSV) 806 lines · 22 elements · HARPS 3780–6910 Å · ESO 1102.D-0954(A)
Section 03
References & Credits
Solar Abundance Reference
Asplund et al. (2021), A&A 653, A141 — A(Fe)☉ = 7.46
Lodders (2003), ApJ 591, 1220 — predecessor reference
Grevesse & Sauval (1998), Space Sci. Rev. 85, 161
Observational Dataset
ESO Program 1102.D-0954(A)
PI: Xavier Dumusque, University of Geneva
10 HARPS S1D spectra · direct solar feed · SNR 306–309
Image Credit
Solar image: Credit NASA/SDO
Orbital map: original illustration · Exoplanet Codex
Planetary Data
NASA Solar System Exploration
IAU 2006 planet definition · 8 planets