Bibliographic record
Abstract
Context. The population of close-in exoplanets features a desert of hot Neptunes whose origin remains uncertain. These planets may have lost their atmosphere, eroding into mini-Neptunes and rocky super-Earths below the desert. Direct observations of evaporating atmospheres are essential to derive mass-loss estimates and constrain this scenario. The metastable He I triplet at 1083.3 nm represents a powerful diagnostic of atmospheric evaporation because it traces the hot gas in extended exoplanet atmospheres while being observed from the ground. In addition, it is located at the bright near-infrared stellar continuum and is very weakly affected by interstellar medium (ISM) absorption. Aims. We carried out a homogeneous He I transmission spectroscopy survey, targeting a selected sample of nine planets along the different edges of the desert, to interpret the absorption line profile with evaporation models and to better understand the role of photoevaporation in the desert formation. Methods. We observed one transit per planet using the high-resolution, near-infrared spectrograph GIANO-B mounted on the Telescopio Nazionale Galileo telescope. We focused our analysis on the He I triplet, based on a comparison of the in-transit and out-of-transit observations, and we computed high-resolution transmission spectra. We then employed the 1D p-winds model to calculate the planetary thermospheric structures and to interpret the observed transmission spectra. Results. We found no signatures of planetary absorption in the He I triplet in any of the investigated targets. We thus provided 3 σ upper-limit estimations on the thermosphere absorption, temperature and mass loss, and combined them with past measurements to search for correlations with parameters such as the stellar mass and XUV flux, which are thought to be key drivers in the formation of the He I triplet. Conclusions. These results strengthen the importance of performing homogeneous surveys and analyses in bringing clarity to He I detections and (thereby) to plausible Neptunian desert origins. Our findings corroborate literature expectations that state the He I absorption signal is correlated with the stellar mass and the received XUV flux. However, when translated in terms of mass-loss rates, these trends seem to disappear. Thus, further studies are essential to shed light on this aspect and to better understand the photoevaporation process.
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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 | 0.002 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.006 | 0.005 |
| Open science | 0.002 | 0.006 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.422 | 0.261 |
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".