Comparison of a pebbles-based model with the observed evolution of the water and carbon dioxide outgassing of comet 67P/Churyumov-Gerasimenko
Bibliographic record
Abstract
ABSTRACT The Rosetta mission escorted comet 67P/Churyumov-Gerasimenko for approximately two years including the perihelion passage (1.24 au, 2015 August), allowing us to monitor the seasonal evolution of the water and carbon dioxide loss rates. Here, we model 67P/Churyumov-Gerasimenko water and carbon dioxide production as measured by the Rosina experiment during the entire escort phase by applying the Water-ice-Enriched Block (WEB) model, namely a structural and activity model for a nucleus made of pebbles. Furthermore, we compare the surface temperature distribution inferred by VIRTIS-M observations in 2014 August (≈3.5 au inbound, northern summer) with the expected temperatures from our simulations in the nucleus’ northern hemisphere, investigating the relevance of self-illumination effects in the comet ‘neck’ and assessing the active area extent during the northern summer. Our simulations imply that: (1) water production at perihelion is mostly from the dehydration of water-poor pebbles, continuously exposed by CO2-driven erosion; (2) at large heliocentric distances outbound the water loss rate is dominated by the self-cleaning of fallout deposits; (3) the outbound steep decrease of the water production curve with heliocentric distance results from the progressive reduction of the nucleus water-active area, as predicted by the proposed model; (4) in 2014 August the water production is dominated by distributed sources, originating in the active ‘neck’; (5) distributed sources originating in water-ice-rich exposures dominate the water production approximately up to the inbound equinox; (6) the time evolution of the CO2 loss rate during the Rosetta escort phase is consistent with the WEB model.
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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 | 0.001 |
| 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".