The Far-Infrared Spectrum of Hydrogenated Amorphous Carbon and the 21, 27, and 33 Micron Features in Carbon-rich Proto–Planetary Nebulae
Bibliographic record
Abstract
We report laboratory emission spectra of hydrogenated amorphous carbon (HAC) in the wavelength range 19 μm < λ < 120 μm (525-83 cm -1 ) at temperatures between 300°C and 500°C. These spectra show emission features at 21, 27, and ≈33 μm (475, 370, and 303 cm -1 ) that can be identified with similar bands in the far-infrared spectra of extreme carbon stars, proto-planetary nebulae, and planetary nebulae. It is suggested that HAC is present in these objects but that the chemical composition of this material depends on the evolutionary state. We also detect a number of broad features at wavelengths longer than 40 μm, attributable to chemical groups in HAC. A strong feature is observed at ≈60 μm (165 cm -1 ) in laboratory spectra and may be present in spectra of the carbon-rich planetary nebula CPD -56°8032. We briefly discuss the nature of the chemical groups responsible for the appearance of these features.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".