Far‐Ultraviolet and Optical Observations of BW Vulpeculae
Bibliographic record
Abstract
We have compared the behavior of 39 Far-Ultraviolet Spectroscopic Explorer spectra through the pulsation cycle of the very large amplitude β Cephei star BW Vul with optical and UV ( IUE ) spectra, as well as optical photometry. The FUSE light curve suggests a temperature amplitude of about 4000 K, while the radial velocity curve is similar to corresponding optical curves, except that the famous "stillstand" feature, due to a shock wave caused by returning infall to the atmosphere from a previous cycle, is slightly weakened. We have performed line syntheses on a number of features in various spectral regions. We find that profiles of the red He I lines (λ6678 and λ5876) at "faint star" and "bright star" phases can be synthesized with standard Kurucz model atmospheres by assuming moderate and high microturbulences, respectively. For the faint-star profile, the line profiles are too deep to be explained other than by lowering the boundary temperature of a standard Kurucz model by 1000-2000 K. This result is confirmed by line syntheses of the far-UV spectra at both phases, which show that fits can be best achieved with models having effective temperatures 4000 K hotter than models fitting optical lines. This result is robust against non-LTE effects. The combined optical and far-UV results suggest that the temperature distributions of both the lower and upper atmosphere are steeper than those computed in (static) Kurucz models. With ad hoc modifications to the atmospheric temperature distribution, we simulated the weakening of the temperature-sensitive C II λλ6578-6583 doublet during shock passages by introducing a uniform shallow temperature gradient through the line formation region. This result agrees with published hydrodynamic results that these shocks produce a plateau-like elevation in gas variables through the atmosphere.
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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".