Composite Spectra, Paper <scp>XXIII</scp>: <scp>HD</scp> 69479/80, a 90‐day binary with a cool‐giant primary
Bibliographic record
Abstract
Abstract HD 69479/80 is a composite‐spectrum binary whose components are a late‐G giant and an early‐A dwarf. The orbit has a period of only 91 days (which seems short for a system containing a cool giant with a radius of ∼13 solar radii), and a very small, but probably significantly non‐zero, eccentricity. We separated the component spectra by a procedure of spectral subtraction, using a standard single giant spectrum as a template, and found the closest match to the spectrum of the cool component to be that of 15 Cyg (G8 III). We measured the radial velocity of the secondary component from each uncovered spectrum, solved the SB2 orbit for the system, and derived a mass ratio m1/m2 of 1.318. Fitting synthetic spectra to the spectra of the secondary component indicated a Teff of 9250 K, log g = 3.75, and a rotational velocity of ∼90 km s−1. We determined the difference in absolute magnitude, δV, between the component stars to be 1.07 mag, the late‐type component being the brighter; we could thence calculate radii and luminosities for both components, plot their H–R diagram positions, and fit evolutionary tracks. The best‐fitting tracks indicated masses of 2.9 M⊙ for the giant and 2.2 M⊙ for the dwarf, which was fully in keeping with the mass ratio given by the SB2 orbit. The track for the dwarf star confirms that this component has begun to evolve away from the ZAMS. Fitting the corresponding isochrone to those H–R diagram positions indicated a log (age) of the system of approximately 8.60 Gyr since the cool star evolved from the ZAMS, which is a little younger than the ages deduced for many cool giants. We also detected the λ 6707‐Å lithium line in the spectrum of the giant component, thus adding to the evidence that it is near the start of its primary ascent of the red‐giant branch.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.028 | 0.005 |
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".