A Preliminary Investigation of the Diffuse Interstellar Line at 8621 Å
Bibliographic record
Abstract
We have obtained high‐resolution spectra at the Dominion Astrophysical Observatory, the Calar Alto Observatory, and the European Southern Observatory of hot stars in the near‐infrared region to study the diffuse interstellar band (DIB) at 8621 Å. Field stars as well as selected members of the Perseus spiral arm, the ρ Ophiuchi complex, and the Cygnus OB2 association were observed and the equivalent widths of the band measured, as well as interstellar K i absorption at 7699 Å. In total we measure the equivalent width of the 8621 band in 64 stars. In a series of figures we show the correlations of the DIB with reddening, polarization, K i , and strengths of other DIBs at 5780, 5797, and 6613 Å. The quality of the correlations are discussed by means of the Spearman rank correlation test. Good correlations are found with reddening and, among the other DIBs, 8621 correlates best with 5780. By examining the three special regions mentioned above we confirm the weakness of the 8621 DIB in the hot stars of the ρ Oph star‐forming region. In the Perseus spiral arm region we find that the DIBs are formed largely in foreground clouds but not in the gas that appears to have been blown away from the young massive stars of the Perseus arm. In Cyg OB2 we find that the equivalent widths of the 8621 line lie above the linear correlation of equivalent width with E(B - V) and their strength does not vary as strongly with reddening. The heavily reddened Cyg OB2 star 12 is the most extreme example of the relative insensitivity of the 8621 equivalent width to reddening in the Cygnus OB2 region.
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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 | 0.001 | 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) | 0.002 | 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".