Cataclysmic Variables: An Empirical Angular Momentum Loss Prescription from Open Cluster Data
Bibliographic record
Abstract
We apply the angular momentum loss rates inferred from open cluster stars to the evolution of cataclysmic variables (CVs). We show that the angular momentum prescriptions used in earlier CV studies are inconsistent with the measured rotation data in open clusters. The timescale for angular momentum loss ( ˙ J) above the fully convective boundary is ∼2 orders of magnitude longer than inferred from the older model, and the observed angular momentum loss properties show no evidence for a change in a behavior at the fully convective boundary. This (1) provides evidence against the hypothesis that the period gap is caused by an abrupt change in the angular momentum loss law when secondary becomes fully convective, (2) implies that evolution of CV is much longer than it was thought, comparable to a Hubble time; for the same reason, it will be more difficult to produce CVs from the products of CE evolution and implies much lower space density of CVs, (3) is consistent with the observed period minimum (1.3 hours) contrary to the minimum predicted by the case when only angular momentum loss due to gravitational radiation works (1.1 hours). We introduce a method to infer time-averaged mass accretion rate and derive mass-period relation for different evolutionary states of the secondary. The mass-period relationship is more consistent with evolved secondaries than with unevolved secondaries above the period gap. Implications for the CV period gap are discussed, including the possibility that two populations of secondaries could produce the gap.
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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 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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 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".