Shells, jets, and internal working surfaces in the molecular outflow from IRAS 04166+2706
Bibliographic record
Abstract
Context. IRAS 04166+2706 in Taurus is one of the closest young stellar objects whose molecular outflow contains a highly collimated, rapidly moving component. Aims. The high symmetry and pristine appearance of this outflow suggests that its study could offer unique clues about the nature of its still mysterious underlying driving wind.Methods. We observed the IRAS 04166+2706 outflow with the IRAM Plateau de Bure interferometer in CO(–1) and SiO(–1), achieving angular resolutions of between and . To improve the quality of the CO(2–1) images, we added single-dish data to the interferometer visibilities.Results. The outflow consists of two distinct components. At velocities of <10 km s-1, the gas forms two opposed, approximately conical shells that have the YSO at their vertex. These shells coincide with the walls of evacuated cavities and appear to result from the acceleration of the ambient gas by a wide-angle wind. At velocities of >30 km s-1, the gas forms two opposed jets that travel along the center of the cavities and whose emission is dominated by a symmetric collection of at least 7 pairs of peaks. The velocity field of this component presents a sawtooth pattern with the gas in the tail of each peak moving more rapidly than the gas at its head. This pattern and a systematic widening of the peaks with distance from the central source are consistent with the emission arising from internal working surfaces traveling along the jet due to variations in the velocity field of ejection. We interpret this component to be the true protostellar wind, and find its composition to be consistent with a chemical model of this wind.Conclusions. Our results favor outflow wind models that have simultaneously wide-angle and narrow components, and suggest that the EHV peaks observed in a number of outflows consist of internally-shocked wind material.
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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 | 0.001 | 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".