Quantitative polarimetry for the transition disk in RX J1604.3-213010
Bibliographic record
Abstract
Context. The characterization of the dust in protoplanetary disks is important for a better understanding of the resulting composition of forming planets and the dust particle evolution in these systems. Aims. We aim to accurately characterize the properties of the dust in the face-on transition disk around RX J1604.3–213010 (RX J1604) by analyzing the multiwavelength scattered light intensity and polarization images obtained with the ZIMPOL and IRDIS subinstruments of VLT/SPHERE. Methods. We used archival data of RX J1604 from the ESO archive and carefully corrected the polarization signal for instrumental effects, also taking the interstellar polarization into account. We measured the radial profiles of the disk for the azimuthal polarization, Qφ(r), in the R, J, and H bands and describe variations in our data due to the seeing and other effects. We derived the intrinsic polarization profiles of the disk, Q^φ(r), by comparing the data with rotationally symmetric models convolved with the point spread functions of the observations. We also measured the disk intensity, Idisk(r), with reference star differential imaging for the J and H bands. This provides the disk-integrated polarized intensity, Q^φ/I⋆, for the R, J, and H bands and the averaged fractional polarization, 〈p^φ〉, for the J and H bands. We investigated the azimuthal dependence of the scattered light and the shadows produced by hot dust near the star. The derived results were finally compared with model calculations to constrain the scattering properties of the reflecting dust in RX J1604. Results. RX J1604 is a dipper source, and the data show different kinds of variability. However, a detailed analysis of repeated measurements shows that the results are not affected by dipping events or atmospheric seeing variations. We derive accurate radial disk profiles for the intrinsic polarized intensity, Q^φ(r)/I⋆, and measure different profile peak radii for different bands because of the wavelength dependence of the dust opacity. The disk-integrated polarization is Q^φ/I⋆ = 0.92 ± 0.04% for the R band and 1.51 ± 0.11% for the J band, indicating a red color for the polarized reflectivity of the disk. The intensity of the disk is Idisk|I* = 3.9 ± 0.5% in the J band, and the fractional polarization is 〈p^φ〉 = 38 ± 4% for the J band and 42 ± 2% for the H band. The comparison with the IR excess for RX J1604 yields an apparent disk albedo of about ΛΙ ≈ 0.16 ± 0.08. We also find that previously described shadows seen in the R band data are likely affected by calibration errors. We derive, using dust scattering models for transition disks, approximate J band values for the scattering albedo ω ≈ 0.5, scattering asymmetry g ≈ 0.5, and scattering polarization pmax ≈ 0.7 for the dust. Conclusions. The bright disk of RX J1604 has a very simple axisymmetric structure and is therefore well suited as a benchmark object for accurate photo-polarimetric measurements. We derive values for the disk polarization, 〈p^φ〉, and the apparent disk albedo, ΛΙ, for the J band. Because 〈p^φ〉 and ΛΙ depend predominantly on dust scattering parameters and only weakly on the disk geometry, these parameters define tight relations for the dust scattering parameters between ω and pmax and between ω and g. The positive R to J band color for the polarized reflectivity, (Q^/I⋆)J ≈ 1.64 ⋅ (Q^/I⋆)R, is mainly a result of the wavelength dependence of dust parameters because the scattering geometry is expected to be very similar for different colors. This work demonstrates the potential of accurate photo-polarimetric measurements of the circumstellar disk RX J1604 for the determination of dust scattering parameters that strongly constrain the physical properties of the dust.
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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) | 0.001 | 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".