<i>FAR ULTRAVIOLET SPECTROSCOPIC EXPLORER</i>OBSERVATIONS OF KPD 2055+3111, A STAR BEHIND THE CYGNUS LOOP
Bibliographic record
Abstract
We have observed a star behind the Cygnus Loop supernova remnant using the Far Ultraviolet Spectroscopic Explorer ( FUSE ) satellite to study the line-of-sight interstellar medium structures toward and through this prototypical remnant. An sdOB star, KPD 2055+3111, was identified from Ultraviolet Imaging Telescope UV images and lies in projection within the bright northeast Cygnus Loop filaments (NGC 6992). This is the first known UV background source for the Cygnus Loop. We have observed this star as well as the directly adjacent emission-line filaments. Although the intrinsic spectrum of the star is complex, a broad O vi λ1032 absorption line due the Cygnus Loop is present in the stellar spectrum, confirming that the star lies beyond the Cygnus Loop. Optical spectroscopy of the star and model fits permits a distance estimate to the star of 576 ± 61 pc, thus providing an independent upper limit on the distance to the Cygnus Loop. Numerous absorption transitions of molecular hydrogen are present in the FUSE spectrum of KPD 2055+3111. Assessment of the properties of the H 2 indicates a column density of (3.3 ± 0.6) × 10 16 cm −2 and a two-temperature J -level population T ( J = 0–1) = 106 ± 40 K and T ( J = 2–5) = 850 ± 230 K. There is no direct evidence from line widths, component structure, or velocity displacements that the detected H 2 is associated with the Cygnus Loop as opposed to the interstellar gas along the sight line, so either source remains viable. The O vi emission line profiles directly adjacent to line of sight to the star show dramatic variability on small (20'') spatial scales, highlighting how differently the UV-emitting gas can be distributed compared with optical and other wave bands. This impacts the ability to directly compare the emission and absorption components along the sight line.
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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 | 0.000 | 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".