Interstellar Deuterium, Nitrogen, and Oxygen Abundances toward BD +28o4211: Results from the <i>FUSE</i> Mission
Bibliographic record
Abstract
High-resolution far-UV spectra of the O-type subdwarf BD +28°4211 were obtained with the Far Ultraviolet Spectroscopic Explorer ( FUSE ) to measure the interstellar deuterium, nitrogen, and oxygen abundances in this direction. The interstellar D I transitions are analyzed down to Lyι at 920.7 Å. The star was observed several times at different target offsets in the direction of spectral dispersion. The aligned and co-added spectra have high signal-to-noise ratios (S/N = 50-100). D I, N I, and O I transitions were analyzed with curve-of-growth and profile fitting techniques. A model of interstellar molecular hydrogen on the line of sight was derived from H 2 lines in the FUSE spectra and used to help analyze some features where blending with H 2 was significant. The H I column density was determined from high-resolution Hubble Space Telescope Space Telescope Imaging Spectrograph spectra of Lyα to be log N (H ) = 19.846 ± 0.035 (2 σ), which is higher than is typical for sight lines in the local interstellar medium (ISM) studied for D/H. We found that D/H = (1.39 ± 0.21) × 10 -5 (2 σ) and O/H = (2.37 ± 0.55) × 10 -4 (2 σ). O/H toward BD +28°4211 appears to be significantly below the mean O/H ratio for the ISM and the Local Bubble.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".