Origin of the hot gas in low-mass protostars
Bibliographic record
Abstract
<i>Aims. <i/>“Water In Star-forming regions with <i>Herschel<i/>” (WISH) is a <i>Herschel<i/> key programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a focus on water and related species.<i>Methods. <i/>The low-mass protostar HH 46 was observed with the Photodetector Array Camera and Spectrometer (PACS) on the <i>Herschel<i/> Space Observatory to measure emission in H<sub>2<sub/>O, CO, OH, [O i], and [C ii] lines located between 63 and 186 <i>μ<i/>m. The excitation and spatial distribution of emission can disentangle the different heating mechanisms of YSOs, with better spatial resolution and sensitivity than previously possible.<i>Results. <i/>Far-IR line emission is detected at the position of the protostar and along the outflow axis. The OH emission is concentrated at the central position, CO emission is bright at the central position and along the outflow, and H<sub>2<sub/>O emission is concentrated in the outflow. In addition, [O i] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km s<sup>-1<sup/> in both the red- and blue-shifted jets. Envelope models are constructed based on previous observational constraints. They indicate that passive heating of a spherical envelope by the protostellar luminosity cannot explain the high-excitation molecular gas detected with PACS, including CO lines with upper levels at >2500 K above the ground state. Instead, warm CO and H<sub>2<sub/>O emission is probably produced in the walls of an outflow-carved cavity in the envelope, which are heated by UV photons and non-dissociative <i>C<i/>-type shocks. The bright OH and [O i] emission is attributed to <i>J<i/>-type shocks in dense gas close to the protostar. In the scenario described here, the combined cooling by far-IR lines within the central spatial pixel is estimated to be 2 × 10<sup>-2<sup/> , with 60–80% attributed to <i>J<i/>- and <i>C<i/>-type shocks produced by interactions between the jet and the envelope.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".