SPIRou detects two planets around the nearby M4.5V star GJ 4274
Bibliographic record
Abstract
Context. M dwarfs are prime targets in the search for exoplanets due to their prevalence and the enhanced radial velocity (RV) detectability of low-mass planets. Recent advancements in instrumentation have extended RV observations from the optical to the near-infrared (nIR) domain, enabling more effective study of M dwarfs, which frequently host rocky planets. The nIR range offers increased RV sensitivity and potentially reduced stellar activity signals, making it particularly well suited for these stars. Aims. We analyzed spectropolarimetric data of the M4.5V star GJ 4274, acquired using the nIR spectropolarimeter SPIRou, to characterize its stellar activity and to search for planetary signals. We additionally examined TESS photometric data to search for transits corresponding to the potential signals in the RV data. Methods. In this study, we employed a line-by-line framework to derive and analyze the RV signal of GJ 4274 acquired with SPIRou. From the SPIRou spectra, we also derived and analyzed the longitudinal large scale magnetic field, B ℓ , and the surface temperature variations, dTemp . We combined the SPIRou RV data with RV measurements from CARMENES, to model possible planetary signals with both circular and eccentric orbits. We modeled the activity with a quasiperiodic Gaussian process. We also performed injection-recovery tests on the photometric TESS data to assess transit detectability. Results. We report the discovery of two exoplanets around the nearby M dwarf star GJ 4274. Both planets are in a circular orbit with respective periods of P b = 1.6339 ± 0.0001 and P c = 69.6 −1.1 +0.3 d, the latter located beyond the habitable zone. From their RV semi-amplitude signals ( K b = 5.10 −0.67 +0.70 m/s and K c = 4.11 ± 0.64 m/s), we derive minimum masses of m b sin i = 2.97 −0.50 +0.54 M ⊕ and m c sin i = 8.4 ± 1.3 M ⊕ , respectively. Photometric observations from TESS rule out most transit scenarios, including for the inner planet, yielding a maximum inclination of i b ≤ 83 ° for planet b. We do not detect RV variations related to stellar magnetic activity in the SPIRou time series, despite a prominent large-scale magnetic field with an amplitude of up to ±206 −62 +158 G. From the activity indicators, we derive a rotation period for the star of 4.600 −0.006 +0.011 d. Conclusions. The two reported planets belong to the sub-Neptune class. GJ 4274 b has one of the shortest orbital periods among planets orbiting <0.2 M ⊙ M dwarfs within 15 pc, while GJ 4274 c lies in a sparsely populated region of the mass–period diagram. Their discovery adds to the census of nearby planetary systems and provides promising targets for future surveys.
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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 | 0.000 |
| 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".