Do the close binaries HD 22128 and HD 56495 contain Ap or Am stars?★
Bibliographic record
Abstract
HD 22128 and HD 56495 are both double-lined spectroscopic binary systems with short orbital periods, which have been proposed to host magnetic Ap stars. Ap stars in short-period binary systems are very rare and may provide insight into the origin of magnetism in A-type stars. We study these two systems using high-resolution MuSiCoS spectropolarimetric data, in order to assess the presence of magnetic fields and study the atmospheric chemistry of the components. This represents the first modern magnetic measurements and careful spectroscopic analyses of these stars. We find no evidence of a magnetic field in any of the stars, with precise uncertainties on the longitudinal magnetic field of 50 and 80 G in the components of HD 22128, and 80 and 100 G in the components of HD 56495. We performed detailed abundance analyses of both stars in both systems, finding clear evidence of Am chemical peculiarities in both components of HD 22128, and in the brighter component of HD 56495, with overabundant iron peak elements and underabundant Sc and Ca. The less luminous component of HD 56495 is chemically normal. The atmospheric chemistry is consistent with the absence of magnetic fields, and consistent with the theory of Am star formation proposing that tidal interactions slow the rotation rate of the star, allowing atomic diffusion to proceed efficiently.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".