The EDIBLES Survey IX: Simulations of the λ6614 DIB Profile Variations: A Surprising Connection with CH<sup>+</sup>
Bibliographic record
Abstract
The profiles of several diffuse interstellar bands (DIBs) show substructures that resemble unresolved rotational bands of the electronic transitions of large molecules. Their profiles show clear variations along the lines of sight, probing different physical conditions. Analysis of variations in such profiles can constrain the sizes and geometries of the DIB carriers and the physical conditions of the interstellar environments in which they reside. We investigate the properties of rotational band contours for perpendicular transitions in planar, oblate symmetric top molecules and compare such contours to the observed profile of the λ6614 DIB. We examine the shapes of the profiles as a function of the model parameters: the rotational constant B in the ground state, the relative change in the rotational constant of the excited state Δ B, the Coriolis coupling constant ζ, the rotational excitation temperature T rot, and line width σ. We determine which parameters can reproduce the overall triple-peak profile of the λ6614 DIB and the variations across different lines of sight. We find that the substructures in the λ6614 DIB can be reproduced with an oblate top with rotational constant B = (2.2 ± 1.8) × 10 –3 cm –1, Δ B = (−7.2 ± 0.4) × 10 –2 %, and Coriolis coupling constant ζ = (2.9 ± 0.1) × 10 –1 cm –1 . Thus, if the λ6614 DIB carrier conforms to an oblate symmetric top geometry, it is most likely to be a ∼54C atom molecule. The profile variations correspond to changes in the rotational temperature from 81 to 92 K. We furthermore find that the intrinsic line width is a key parameter for each sightline and requires a range from 0.14 to 0.21 cm –1 (or 2.8 to 4.2 km s –1 ) across our sample to reproduce the observations. The intrinsic line width of the λ6614 DIB correlates with the width of the CH + lines, suggesting an origin in the same environment. We conclude that the λ6614 DIB carrier resides in the same hot gas at low density that is probed by CH + .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 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) | 0.000 | 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 teacher head, 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".