The ZZ Ceti Instability Strip for the Most Massive White Dwarf Pulsators
Bibliographic record
Abstract
Abstract We present time-series photometry of 31 massive DA white dwarfs with M ≳ 0.9 M ⊙ within the ZZ Ceti instability strip from the Montreal White Dwarf Database 100 pc sample. The majority of the targets had no previous time-series photometry available, though several were classified as nonvariable or potential pulsators in the literature. Out of the 31 candidates, we confirm 16 as pulsating. Our observations at three observatories have led us to discover the most massive pulsating white dwarf currently known, J0959−1828 ( M = 1.32 or 1.27 M ⊙ for a CO versus ONe core), which is slightly more massive than the previous record holder J0049−2525. We study the sample properties of massive ZZ Ceti white dwarfs and find several trends with their weighted mean periods. As predicted by theory, we see an increase in the weighted mean periods with decreasing effective temperature and a decrease in pulsation amplitudes at the red edge of the instability strip. Furthermore, the weighted mean periods decrease with increasing stellar mass. Our observations show that the ZZ Ceti instability strip may not be pure at high masses. This is likely because the nonvariable white dwarfs in the middle of the strip may be weakly magnetic, which could escape detection in the available low-resolution spectroscopy data, but may be sufficient to suppress pulsations. Extensive follow-up observations of the most massive white dwarfs in our sample have the potential to probe the interior structures and core compositions of these white dwarfs with significantly crystallized cores.
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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 | 0.000 | 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) | 0.002 | 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".