Characterization of South polar-winds in Neptune’s atmosphere from ALMA observations
Bibliographic record
Abstract
Measurements of winds in Neptune's stratosphere obtained by ALMA Doppler spectroscopy in 2016 by [1] have shown that stratospheric zonal winds at a pressure level of 1 mbar (-180 m/s) appear to be less intense, by a factor of two, than tropospheric winds based on cloud tracking at 1 bar from Voyager observations (-400 m/s). These data also indicate a reversal of the circulation, from retrograde to prograde, at high southern latitudes. However, the spatial resolution of these data was insufficient for a detailed characterization of the high-latitude circulation.We present here higher spatial resolution ALMA maps of CO and HCN emission lines towards Neptune's limb to measure their Doppler shifts and derive a map of zonal winds in its stratosphere. Our observations - carried out in March-April 2025 - used the ALMA interferometer to map the CO(3-2) and HCN(5-4) rotational lines in Neptune's atmosphere at 345.796 and 354.505 GHz, respectively. These measurements were obtained using around 44 antennas of the 12m array, with an angular resolution of ~0.19'', allowing the mapping of around 12x12 independent pixels on the planetary disk (2.21").We will present the analysis of these observations, which will include maps of the planet's zonal wind after subtraction of the planet's solid rotation, and compare these results with earlier measurements of the Doppler wind in Neptune's atmosphere [1]. Particular attention will be paid to the South Pole region, whose resolution will be improved by a factor of 2 compared with the observations of [1]. This growing ensemble of ALMA datasets opens the door to the long-term monitoring of the seasonal stability and potential variations of Neptune's stratospheric wind patterns.AcknowledgementsALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.References [1] Carrion-Gonzalez et al. 2023 A&A 674, L3
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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) | 0.000 | 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 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".