The Masses of White Dwarfs in the Praesepe Open Cluster
Bibliographic record
Abstract
We present results from an in-depth photometric and spectroscopic study of white dwarfs in the Praesepe open cluster. From high signal-to-noise ratio spectra, we have estimated log g and T eff for six DA white dwarfs using model atmosphere fits to the Balmer lines. Evolutionary models are then used to determine masses, radii, and cooling times. Good agreement is found with masses determined using gravitational redshifts primarily by Reid and with masses determined from the cluster's distance. Included in these comparisons are white dwarfs analyzed in a similar way in the Hyades and Pleiades clusters. The cooling times and cluster ages are then used to determine initial masses ( M i ) for each white dwarf. A monotonic initial-final mass relation ( M i - M f ) is determined for these and two other well-studied clusters, although there are indications that more envelope mass is lost in the asymptotic red giant branch thermal pulse phase than current theory predicts. One Praesepe object—LB 5893 (0836+197)—is anomalous in the sense that it has the highest M f but the highest T eff and the smallest inferred M i . LB 393 = EG 61 (0837+199) shows Zeeman-split lines indicative of a strong magnetic field, the first such white dwarf found in a star cluster.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".