Color measurements of the polarized light scattered by the dust in protoplanetary disks
Bibliographic record
Abstract
Ground-based high-contrast instruments have yielded reflected light images of protoplanetary disks. Quantitative measurements of the reflected radiation provide strong constraints on the scattering dust which can clarify the dust particle evolution in these disks and the composition of the forming planets. This study aimed to derive the wavelength dependence of polarized reflectivity $(\hat{Q}_φ/I_\star)_λ$ for 11 disks, constraining dust properties and identifying systematic differences. Using ESO archive data from SPHERE/ZIMPOL and SPHERE/IRDIS instruments, we obtained accurate intrinsic polarized reflectivity $\hat{Q}_φ/I_\star$ values at wavelengths from 0.62$μ$m to 2.2$μ$m. Polarized reflectivities ranged from $Q_φ/I_\star\approx 0.1\%$ to 1.0$\%$, with PSF-corrected values averaging 1.6 times higher than observed. Accurate PSF calibrations reduced systematic errors to $Δ\hat{Q}_φ/\hat{Q}_φ\approx 10\%$ or less. For each disk, we derived a polarized reflectivity color $η_{V/IR}$ between a visible band $λ<1~μ$m and a near-IR band $λ>1~μ$m and other wavelength combinations. Wavelength gradients $η$ varied significantly among objects. Disks around Herbig stars (HD 169142, HD 135334B, HD 100453, MWC 758, and HD 142527) showed a red color $η_{\rm V/IR}>0.5$, suggesting rather compact dust grains. T-Tauri star disks (PDS 70, TW Hya, RX J1615, and PDS 66) were predominantly gray $-0.5<η_{\rm V/IR}<0.5$, with an absence of blue colors incompatible with porous aggregates. Exceptional red colors for LkCa15 and MWC758 were attributed to potential extra reddening from hot dust near the star. Future studies incorporating parameters like fractional polarization $\langle p_φ\rangle$ hold promise for advancing our understanding of dust properties within protoplanetary disks.
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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".