EXCITATION OF EXTENDED RED EMISSION AND NEAR-INFRARED CONTINUUM RADIATION IN THE INTERSTELLAR MEDIUM
Bibliographic record
Abstract
Many small molecules including carbon clusters emit blackbody radiation in the visible spectrum when their internal temperature, T , is raised above 2000 K by photoabsorption. Blackbody emission is known to be the dominant cooling mechanism for small dehydrogenated carbon molecules for 1500 < T < 3000 K. The condition that T > 2000 K would be met by interstellar molecules containing ≤28 carbon atoms, heated by energetic photons from the interstellar radiation field. It is shown here that thermal emission will augment photoluminescent emission in extended red emission (ERE) sources when the UV radiation field is enhanced. In particular, this mechanism provides a simple explanation for observations that show that only stars with T eff > 7000 K excite the ERE. The observation by Witt et al. that photons with energies >10.5 eV are required for the onset of ERE emission can then be interpreted as the condition for the initiation of thermal emission at visible wavelengths. These observational requirements have been combined with laboratory and theoretical data to constrain the emitters of the ERE to dehydrogenated carbon molecules, C N with 20 ≤ N ≤ 28 atoms. The composition and structure of these molecules is discussed and IR band energies for several possible C N species are provided. These molecules are stable against photodissociation in the interstellar radiation field. It is also shown that dimers of these molecules, (C N ) 2 , may be the species that give rise to the near-infrared continuum first detected by Sellgren. A new effect that might be significant under interstellar conditions involving unimolecular rearrangement reactions in thermally excited molecules is also discussed.
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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 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".