Accurate fundamental parameters for 23 bright solar-type stars
Bibliographic record
Abstract
We combine results from interferometry, asteroseismology and spectroscopy to determine accurate fundamental parameters of 23 bright solar-type stars, from spectral type F5 to K2 and luminosity classes III-V.For some stars we can use direct techniques to determine the mass, radius, luminosity and effective temperature, and we compare with indirect methods that rely on photometric calibrations or spectroscopic analyses.We use the asteroseismic information available in the literature to infer an indirect mass with an accuracy of 4-15 per cent.From indirect methods we determine luminosity and radius to 3 per cent.We find evidence that the luminosity from the indirect method is slightly overestimated (≈5 per cent) for the coolest stars, indicating that their bolometric corrections (BCs) are too negative.For T eff we find a slight offset of -40 ± 20 K between the spectroscopic method and the direct method, meaning the spectroscopic temperatures are too high.From the spectroscopic analysis we determine the detailed chemical composition for 13 elements, including Li, C and O.The metallicity ranges from [Fe/H] = -1.7 to +0.4, and there is clear evidence for α-element enhancement in the metal-poor stars.We find no significant offset between the spectroscopic surface gravity and the value from combining asteroseismology with radius estimates.From the spectroscopy we also determine v sin i and we present a new calibration of macroturbulence and microturbulence.From the comparison between the results from the direct and spectroscopic methods we claim that we can determine T eff , log g and [Fe/H] with absolute accuracies of 80 K, 0.08 and 0.07 dex.Photometric calibrations of Strömgren indices provide accurate results for T eff and [Fe/H] but will be more uncertain for distant stars when interstellar reddening becomes important.The indirect methods are important to obtain reliable estimates of the fundamental parameters of relatively faint stars when interferometry cannot be used.This paper is the first to compare direct and indirect methods for a large sample of stars, and we conclude that indirect methods are valid, although slight corrections may be needed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".