Ultraviolet Eclipse Observations and Fundamental Parameters of the Binary HR 2554 (G6 II+A1 V)
Bibliographic record
Abstract
HR 2554 is an eclipsing binary system that contains a G6 II primary star and an A dwarf secondary. We have obtained ultraviolet spectra during two eclipses of HR 2554 in 1994 March–April and 1995 May using the HST Goddard High Resolution Spectrograph (GHRS) to study the atmospheric structure of the primary and to better establish the properties of the binary system. We have determined accurate orbital elements for both components, using new and existing optical spectra for the primary and the GHRS spectra for the secondary, in conjunction with eclipse photometry presented in 1992 by Schröder & Hünsch. The derived orbital period is 195.258 ± 0.003 days, the derived radii are 31.3 ± 0.9 R ⊙ and 1.9 ± 0.1 R ⊙ , and the derived masses are 3.14 ± 0.17 M ⊙ and 1.98 ± 0.11 M ⊙ , respectively. The resulting positions of HR 2554 in the Hertzsprung-Russell (H-R) diagram are somewhat inconsistent with the independent evolution of the component stars; in particular, the G star primary is both overluminous and too blue for its mass. The difficulties might be overcome if the metallicity of the system were unusually low ([Fe/H] ∼ -1), but this possibility appears to be ruled out by the [Fe/H] = -0.04 determination of Eggen. We suspect HR 2554 has undergone a more complicated evolutionary history involving mass transfer than has been considered previously.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".