Keplerian motion of a compact source orbiting the inner disc of PDS 70: a third protoplanet in resonance with b and c?
Bibliographic record
Abstract
ABSTRACT The disc around PDS 70 hosts two directly imaged protoplanets in a gap. Previous VLT/SPHERE and recent JWST/NIRCam observations have hinted at the presence of a third compact source in the same gap at $\sim$13 au, interior to the orbit of PDS 70 b. We reduce seven published and one unpublished VLT/SPHERE data sets in YJH and K bands, as well as an archival VLT/NaCo data set in L’ band, and an archival VLT/SINFONI data set in H + K band. We combine angular-, spectral-, and reference star differential imaging to search for protoplanet candidates. We recover the compact source in all epochs, consistent with the JWST detection, moving on an arc that can be fit by Keplerian motion of a protoplanet that could be in resonance with PDS 70 b and c. We find that the spectral slope is overall consistent with the unresolved star and inner disc emission at 0.95–1.65 $\mu\mathrm{m}$, which suggests a dust-scattering-dominated spectrum. An excess beyond 2.3 $\mu\mathrm{m}$ could be thermal emission from either a protoplanet or heated circumplanetary dust, variability, or inner disc contamination, and requires confirmation. While we currently cannot rule out a moving inner disc feature or a dust clump associated with an unseen planet, the data support the hypothesis of a third protoplanet in this remarkable system.
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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 | 0.001 | 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".