Physical Properties of Fullerene-containing Galactic Planetary Nebulae
Bibliographic record
Abstract
We searched the Spitzer Space Telescope data archive for Galactic planetary nebulae (PNe), that show the characteristic 17.4 and 18.9 µm features due to C 60 , also known as buckminsterfullerene. Out of 338 objects with Spitzer/IRS data, we found eleven C 60 -containing PNe, six of which (Hen2-68, IC2501, K3-62, M1-6, M1-9, and SaSt2-3) are new detections.The strongest 17.4 and 18.9 µm C 60 features are seen in Tc 1 and SaSt 2-3, and these two sources also prominently show the C 60 resonances at 7.0 and 8.5 µm.In the other nine sources, the 7.0 and 8.5 µm features due to C 60 are much weaker.The flux ratio between the 17.4 and 18.9 µm C 60 feature is rather constant amongst the sample, with an average value of 0.49.We find that the Polycyclic Aromatic Hydrocarbon (PAH) profile over 6-9 µm in these C 60 -bearing carbon-rich PNe is of the more chemically-processed class A. The Spitzer spectra also show broad dust features around 11 and 30 µm.The strength of the 11-µm feature is correlated to the temperature of the dust, suggesting that it is at least partially due to a solid-state carrier. The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments 18-22 November,
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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 | 0.001 | 0.001 |
| 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".