ATREIDES
Bibliographic record
Abstract
The distribution of close-in exoplanets is shaped by a complex interplay between atmospheric and dynamical processes. The Desert, Ridge, and Savanna (respectively a lack, overoccurence, and mild deficit of Neptunes with increasing periods) illustrate the sensitivity of these worlds to such processes, making them ideal targets to disentangle their roles. Determining how many Neptunes are brought close-in by early disk-driven migration (DDM; expected to maintain primordial spin-orbit alignment) or late high-eccentricity tidal migration (HEM; expected to generate large misalignments) is essential to understanding how much atmosphere they lost. In this paper, we propose a unified view of the exo-Neptunian landscape to guide its exploration and speculate that the Ridge is a hot spot for evolutionary processes. Low-density Neptunes would mainly undergo DDM, becoming fully eroded at shorter periods than the Ridge. This is in contrast to denser Neptunes, which would be brought to the Ridge and Desert by HEM. We embark on this exploration via the ATREIDES (Ancestry, Traits, and Relations of Exoplanets Inhabiting the Desert Edges and Savanna) collaboration, which relies on spectroscopic and photometric observations of ~60 close-in Neptunes, their reduction with robust pipelines, and their interpretation through internal structure, atmospheric, and evolutionary models. We carried out a systematic Rossiter-McLaughlin census with VLT/ESPRESSO to measure the distribution of 3D spin-orbit angles, correlate its shape with the system properties (orbit, density, evaporation), and thus relate the fraction of aligned-misaligned Neptunian systems to DDM, HEM, and atmospheric erosion. The first ATREIDES target, TOI-421 c, lies in the Savanna with a neighboring sub-Neptune TOI-421 b. We measured for the first time their 3D spin-orbit angles ( ψ b = 57 −15 +11∘ ; ψ c = 44.9 −4.1 +4.4∘ ). Together with the eccentricity and possibly large mutual inclination of their orbits, this hints at a chaotic dynamical origin that could result from DDM followed by HEM. Our program will provide the community with a wealth of constraints for formation and evolution models, and we welcome collaborations that will contribute to pushing our understanding of the exo-Neptunian landscape forward.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.028 | 0.029 |
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".