First results from hydrodynamic simulations of convective-reactive proton-C12 combustion in the He-shell flash of Sakurai's object
Bibliographic record
Abstract
The mixing of proton-rich material into C-rich He-shell flash convection induces exotic n-capture nucleosynthtesis and is encountered in the late phases of the evolution of different types of stars. Examples include the first generations of lowand intermediate mass and massive stars that formed in the early Universe. The He-shell flash convection during the post-AGB evolution provides a solarlike metallicity example of a H-ingestion event that can validate multi-physics simulations. Previously we have demonstrated that light curve and abundance observations of post-AGB star Sakurai’s object can only be reproduced by stellar evolution simulations if mixing-length theory mixing properties are modified. Our initial 3D simulations of the entrainment and burning of protons into the He-shell flash convection zone confirm some properties of stellar evolution models and identify aspects that are not correctly described in 1D models. 3D and 1D simulations aggree in that a H-burning driven convection zone emerges inside the original He-shell flash convection zone after a relatively short time after the H-ingestion starts, in terms of the entrained mass of protons. The location of the H-burning convection zone in the 3D simulation only agrees with a 1D model in which the mixing efficiency is calibrated to reproduce the light curve. Unlike stellar evolution predictions we have no evidence in 3D hydrodynamic simulations for the formation of a strict mixing split between the two convection zones up to the end of our present simulations at ≈ 10hr, consistent with our previous analysis of nucleosynthesis constraints. Subject headings: stars: AGB and post-AGB, evolution, interior, individual (V4334 Sagittarii) — physical data and processes: turbulence, hydrodynamics, convection
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".