Debris discs at centimetre wavelengths: planetesimal populations in young extrasolar Kuiper belts
Bibliographic record
Abstract
ABSTRACT Two luminous debris discs around 100 Myr old have been searched for 1 cm dust emission, to a depth three times greater than in any such previous study. Very low limits were set towards both HD 377 and HD 104860 (noise levels of 12–14 Jy), extending the spectral range from 70 m to 3 mm where cool dust has previously been sought. The almost-identical fluxes of the two systems were merged into an average spectral energy distribution, which was then fitted using a distribution of grain sizes. The canonical infinite collisional cascade, with numbers of particles n(D) ∝ D−3.5 for diameter D, overpredicts the 1-cm flux, which should have been detected at over 3σ for the merged system. Preferred solutions have truncated grain populations with largest particles around 1.5–4 mm in diameter, and slightly flatter distributions, up to n(D) ∝ D−3.1. The lack of cm-sized and larger particles is reminiscent of the similar deficit inferred around comets from spacecraft encounters. Such departures from simple power-law distributions of particles have been predicted in recent models where some size regimes are more readily broken up than others. A deficit of cm-scale particles can explain the fits we obtain, and reduces the total masses inferred for the comet belts of these stars.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".