A Planet as the Possible Cause of the HD 181327 Debris Disk Asymmetry
Bibliographic record
Abstract
ABSTRACT The debris disc around HD 181327 shows a significant asymmetry in its surface brightness profile when viewed in visible light. Observations from the Hubble Space Telescope STIS instrument show an arc of approximately 90$^\circ$ of higher optical depth at a distance of 84 au from the star. Here, we explore whether a planet could be the driver of this asymmetry. Through N-body simulations, we find that a 2–4 Jupiter-mass planet on a circular orbit at 70 au can produce and maintain a similar feature if the collisional lifetime of dust in the disc is between 4 and 8 kyr, so long as a modest fraction of the grains are ejected with high ($\lesssim$1 km s$^{-1}$) speeds. We also find that the surface brightness asymmetry is much less pronounced at larger particle sizes, which may account for the fact that observations of HD 181327 at longer wavelengths have not reported such an arc.
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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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".