Searching for close-in planets around TWA 7 with SPIRou
Bibliographic record
Abstract
We outline in this paper observations of the young pre-main-sequence low-mass star TWA 7 hosting a debris disk and a distant planet. Using data collected with the near-infrared SPIRou spectropolarimeter and precision velocimeter at the Canada-France-Hawaii Telescope from early 2019 to mid 2021, we detected the magnetic field of TWA 7 from the circularly polarized Zeeman signatures and Zeeman broadening of atomic spectral lines and the rotational modulation of its longitudinal component at the known stellar rotation period (of 5.012 ± 0.007 d). We then modeled the large-scale and small-scale magnetic properties of TWA 7 using Zeeman-Doppler imaging. We find that TWA 7 hosted a mainly poloidal field that significantly evolved from 2019 to 2021 and that the dipole component became stronger (increasing from 0.5 kG in 2019 to 0.7 kG in 2021) and less inclined to the stellar rotation axis (from 22° in 2019 to 15° in 2021). We also analyzed the radial velocities of TWA 7 derived from the SPIRou data and found a tentative planet signature at a period of 15.2 d (with aliases at 20.8 and 30.4 d), which is very close to the detection limit of our data and would correspond to a 0.17 M♃ planet at a distance of 0.09 au if confirmed. Finally, we report that the 1083 nm He I and 1282 nm Paβ lines of TWA 7 are modulated with a period of 6.6 d, different from the rotation period. This potentially hints at the presence of a close-in planet triggering star-planet interactions.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 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".