A Young Ultramassive White Dwarf in the AB Doradus Moving Group
Bibliographic record
Abstract
We use Gaia DR2 kinematic data and white dwarf evolutionary models to determine that the young and ultramassive white dwarf GD 50 is a likely member of the AB Doradus moving group. Comparison with the Montréal white dwarf evolutionary models and the MIST main-sequence lifetimes imply a total age of 117 $\pm$ 26 ($\pm$ 13 statistic, $\pm$ 22 systematic) Myr, accounting for all possible C/O/Ne core compositions and using the Pleiad white dwarf LB 1497 as a comparison benchmark. This is the first white dwarf cosmochronology age for a nearby young moving group, and allows us to refine the age of the AB Doradus moving group at 133$_{-20}^{+15}$ Myr by combining it with its independent isochronal age. GD 50 is the first white dwarf member of the AB Doradus moving group and is located at only 31 pc from the Sun, making it an important benchmark to better understand the star-formation history of the Solar neighborhood.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".