The destruction and survival of dust in the shell around SN 2008S
Bibliographic record
Abstract
SN 2008S erupted in early 2008 in the grand design spiral galaxy NGC 6946. The progenitor was detected by Prieto et al. in Spitzer Space Telescope images taken over the four years prior to the explosion, but was not detected in deep optical images, from which they inferred a self-obscured object with a mass of about 10 M⊙. We obtained Spitzer observations of SN 2008S 5 days after its discovery, as well as coordinated Gemini and Spitzer optical and infrared observations 6 months after its outburst. We have constructed radiative transfer dust models for the object before and after the outburst, using the same r−2 density distribution of pre-existing amorphous carbon grains for all epochs and taking light travel time effects into account. We rule out silicate grains as a significant component of the dust around SN 2008S. The inner radius of the dust shell moved outwards from its pre-outburst value of 85 au to a post-outburst value of 1250 au, attributable to grain vaporization by the light flash from SN 2008S. Although this caused the circumstellar extinction to decrease from AV= 15 before the outburst to 0.8 after the outburst, we estimate that less than 2 per cent of the overall circumstellar dust mass was destroyed. The total mass-loss rate from the progenitor star is estimated to have been 0.5–1.0 × 10−4 M⊙ yr−1. The derived dust-mass-loss rate of 5 × 10−7 M⊙ yr−1 implies a total dust injection into the interstellar medium of up to 0.01 M⊙ over the suggested duration of the self-obscured phase. We consider the potential contribution of objects like SN 2008S to the dust enrichment of galaxies.
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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 | 0.000 |
| 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) | 0.000 | 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".