THE ABUNDANCE OF H<sub>2</sub>O AND HDO IN ORION KL FROM<i>HERSCHEL</i>/HIFI
Bibliographic record
Abstract
Using a broadband, high spectral resolution survey toward the Orion Kleinmann–Low nebula acquired with Herschel /HIFI as part of the Herschel Observations of Extra-Ordinary Sources key program, we derive the abundances of H 2 O and HDO in the different spatial/velocity components associated with this massive star-forming region: the Hot Core, Compact Ridge, and Plateau. A total of 20 transitions of H 2 18 O, 14 of H 2 17 O, 37 of HD 16 O, 6 of HD 18 O, and 6 of D 2 O are used in the analysis, spanning from ground state transitions to over 1200 K in upper-state energy. Low-excitation lines are detected in multiple components, but the highest-excitation lines ( E u > 500 K) are well modeled as emitting from a small (∼2'') clump with a high abundance of H 2 O (χ = 6.5 × 10 −4 relative to H 2 ) and a HDO/H 2 O ratio of 0.003. Using high spatial resolution (1 5 × 1 1) images of two transitions of HDO measured by the Atacama Large Millimeter/Submillimeter Array as part of its science verification phase, we identify this component as located near, but not directly coincident with, known continuum sources in the Hot Core region. Significant HDO/H 2 O fractionation is also seen in the Compact Ridge and Plateau components. The outflowing gas, observed with both emission and absorption components, has a lower HDO/H 2 O ratio than the compact components in Orion Kleinmann–Low, which we propose could be due to modification by gas-phase shock chemistry.
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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) | 0.001 | 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".