Bibliographic record
Abstract
Context. Understanding the connection between outflows, winds, accretion, and discs in the inner protostellar regions is crucial for comprehending star and planet formation processes. Aims. We aim to we explore the inner 300 au of the protostar IRAS 4A2 as part of the ALMA FAUST Large Program. Methods. We analysed the kinematical structures of SiO and CH3OH emission with 50 au resolution. Results. The emission arises from three zones: (i) a very compact and unresolved region (< 50 au) dominated by the ice sublimation zone, at ±1.5 km s−1 with respect to vsys, traced by methanol; (ii) an intermediate region (between 50 au and 150 au) traced by both SiO and CH3OH, between 2 and 6 km s−1 with respect to vsys, with an inverted velocity gradient (with respect to the large-scale emission), whose origin is not clear; (iii) an extended region (> 150 au) traced by SiO, above 7 km s−1 with respect to vsys, and dominated by the outflow. In the intermediate region, we estimated a CH3OH/SiO abundance ratio of about 120–400 and a SiO/H2 abundance of 10−8. We explored various possibilities to explain the origin of this region, such as, a rotating disc or inner envelope, a jet on the plane of the sky or precessing, and a wide-angle disc wind. Conclusions. We propose that CH3OH and SiO in the inner 100 au probe the base of a wide-angle disc wind. The material accelerated in the wind crosses the plane of the sky, giving rise to the observed inverted velocity gradient, and sputtering the grain mantles and cores releasing CH3OH and SiO. This is the first detection of a disc-wind candidate in SiO, and the second ever in CH3OH.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.337 | 0.181 |
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".