Instabilities in the ionization zones around the first stars
Bibliographic record
Abstract
We consider the evolution of the ionization zone around Population III stars with M * ∼ 25–200M ⊙ in protogalaxies with M ∼ 107 M ⊙ at redshifts z = 12, assuming that the dark-energy profile is a modified isothermal sphere. We study the conditions for the growth of instabilities in the ionization zones. The Rayleigh-Taylor and thermal instabilities develop efficiently in the ionization zones around 25–40M ⊙ stars, while this efficiency is lower for stars withM * ∼ 120M ⊙. For more massive stars (∼200M ⊙), the flux of ionizing photons is strong enough to considerably reduce the gas density in the ionization zone, and the typical lifetimes of stars (∼2 Myr) are insufficient for the growth of instabilities. The gas in a protogalaxy with M ∼ 107 M ⊙ with a 200M ⊙ central star is completely ionized by the end of the star’s lifetime; in the case of a 120M ⊙ central star, only one-third of the total mass of gas is ionized. Thus, ionizing photons from stars with M * ≲ 120M ⊙ cannot leave protogalaxies with M ≳ 107 M ⊙. If the masses of the central stars are 25 and 40M ⊙, the gas in protogalaxies of this mass remains essentially neutral. We discuss the consequences of the evolution of the ionization zones for the propagation of the envelope after the supernova explosions of the strs and the efficiency of enrichment of the intergalactic medium in heavy elements.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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 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".