The TOI-1117 multiplanetary system: 3 sub-Neptunes, 1 in both the Neptunian Desert and Radius Valley
Bibliographic record
Abstract
ABSTRACT We present the discovery of three sub-Neptune planets around TOI-1117, a Sun-like star with mass $0.97\pm 0.02\,{\mathrm M}_{\odot }$, radius $1.05\pm 0.03\,{\mathrm {R}}_{\odot }$, age $4.42\pm 1.50$ Gyr, and effective temperature $5635\pm 62$ K. Light curves from Transiting Exoplanet Survey Satellite and Las Cumbres Observatory Global Telescope show a transiting sub-Neptune with a 2.23-d period, mass $M_b=8.90_{-0.96}^{+0.95}\,\mathrm{ M}_{\rm{\oplus }}$ and radius $R_b=2.46_{-0.12}^{+0.13}\,\mathrm{ R}_{\rm{\oplus }}$. This is a rare ‘hot Neptune’ that falls within the parameter spaces known as the ‘Neptunian Desert’ and the ‘Radius Valley’. Two more planetary signals are detected in HARPS (High Accuracy Radial velocity Planetary Searcher) radial velocities, revealing two non-transiting planets with minimum masses $M_c=7.46_{-1.62}^{+1.43}\,\mathrm{ M}_{\rm{\oplus }}$ and $M_d=9.06_{-1.78}^{+2.07}\,\mathrm{ M}_{\rm{\oplus }}$, and periods of $4.579\pm 0.004$ and $8.67\pm 0.01$ d. The eccentricities were poorly constrained by the HARPS data, with upper limits $e_b=0.11$, $e_c=0.29$, and $e_d=0.24$. However, dynamical simulations of the TOI-1117 system, suggest that the orbits must be nearly circular to be stable. The simulations also show that TOI-1117 b and c are likely to be in a near 2:1 resonance. The multiplanet nature of TOI-1117 makes it a more complex case for formation theories of the Neptunian Desert and Radius Valley, as current theories such as high-eccentricity migration are too turbulent to produce a stable, non-eccentric, and multiplanet system. Moreover, analysis of TOI-1117 b’s photoevaporation history found rocky core and H/He atmosphere models to be inconsistent with observations, whilst water-rich scenarios were favoured.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".