VLTI/MIDI observations of 7 classical Be stars
Bibliographic record
Abstract
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar envelope that is responsible for the observed IR-excess and emission lines. The origin of this envelope, its geometry, and kinematics have been debated for some time.Aims. We measured the mid-infrared extension of the gaseous disk surrounding seven of the closest Be stars in order to constrain the geometry of their circumstellar environments and to try to infer physical parameters characterizing these disks.Methods. Long baseline interferometry is the only technique that enables spatial resolution of the circumstellar environment of classical Be stars. We used the VLTI/MIDI instrument with baselines up to 130 m to obtain an angular resolution of about 15 mas in the N band and compared our results with previous K band measurements obtained with the VLTI/AMBER instrument and/or the CHARA interferometer.Results. We obtained one calibrated visibility measurement for each of the four stars, p Car, ζ Tau, κ CMa, and α Col, two for δ Cen and β CMi, and three for α Ara. Almost all targets remain unresolved even with the largest VLTI baseline of 130 m, evidence that their circumstellar disk extension is less than 10 mas. The only exception is α Ara, which is clearly resolved and well-fitted by an elliptical envelope with a major axis mas and an axis ratio at 8 μm. This extension is similar to the size and flattening measured with the VLTI/AMBER instrument in the K band at 2 μm.Conclusions. The size of the circumstellar envelopes for these classical Be stars does not seem to vary strongly on the observed wavelength between 8 and 12 μm. Moreover, the size and shape of α Ara's disk is almost identical at 2, 8, and 12 μm. We expected that longer wavelengths probe cooler regions and correspondingly larger envelopes, but this is clearly not the case from these measurements. For α Ara this could come from to disk truncation by a small companion; however, other explanations are needed for the other targets.
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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 | 0.001 |
| 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) | 0.001 | 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".