A chemical map of the outbursting V883 Ori system: vertical and radial structures
Bibliographic record
Abstract
ABSTRACT We present the first results of a pilot program to conduct an Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 (211–275 GHz) spectral line study of young stellar objects (YSOs) that are undergoing rapid accretion episodes, i.e. FU Ori objects (FUors). Here, we report on molecular emission line observations of the FUor system, V883 Ori. In order to image the FUor object with a full coverage from ∼0.5 arcsec to the map size of ∼30 arcsec, i.e. from disc to outflow scales, we combine the ALMA main array (the 12-m array) with the Atacama Compact Array (7-m array) and the Total Power (TP) array. We detect HCN, HCO+, CH3OH, SO, DCN, and H2CO emission with most of these lines displaying complex kinematics. From position–velocity (PV) diagrams, the detected molecules HCN, HCO+, CH3OH, DCN, SO, and H2CO probe a Keplerian rotating disc in a direction perpendicular to the large-scale outflow detected previously with the 12CO and 13CO lines. Additionally, HCN and HCO+ reveal kinematic signatures of infall motion. The north outflow is seen in HCO+, H2CO, and SO emission. Interestingly, HCO+ emission reveals a pronounced inner depression or ‘hole’ with a size comparable to the radial extension estimated for the CH3OH and 230 GHz continuum. The inner depression in the integrated HCO+ intensity distribution of V883 Ori is most likely the result of optical depth effects, wherein the optically thick nature of the HCO+ and continuum emission towards the innermost parts of V883 Ori can result in a continuum subtraction artefact in the final HCO+ flux level.
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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 | 0.000 | 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) | 0.002 | 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".