Fix the reading target
The first target is Han and collaborators, ARKS II: The radial structure of debris discs, arXiv 2601.13670 v1, 20 January 2026, linked to the published A&A 705 A196 record. Read section 2 for profile construction, section 4.3 and Figure 8 for the conditional gap-to-planet map, and Appendix H for possible commensurabilities. The second target is Lovell and collaborators, ARKS VI: Asymmetries and offsets, arXiv 2601.11766 v1, 16 January 2026, linked to A&A 705 A200. Read section 2.2, section 3.1.7 with Figure 6, and sections 4.1–4.2.
Those are fixed full-text reading targets. The notes below refer to that fixed version. Primary text was checked at the assigned sections and figure captions. The associated Harvard products were not accessible during preparation, so no ARKS data reanalysis or reproduction is claimed. The public numerical package uses a separate REASONS SMA image.
Reading: Han et al. · ARKS II, arXiv 2601.13670v1 · Lovell et al. · ARKS VI, arXiv 2601.11766v1 · Matrà · REASONS archive 12583396, version v0.0, CC BY 4.0
Put the measurement in the left column
For ARKS II, identify whether each radial feature comes from a CLEAN profile, a nonparametric inversion or a parametric visibility model. In Figure 8, the plotted planet masses assume a single circular in-situ planet and a specified gap-clearing prescription. Gap depth was not used to validate those width-based masses. Appendix H explicitly leaves chance proximity to period commensurabilities unresolved.
Make a two-column note. On the left, write the measured or modeled feature and its response to resolution. On the right, write the additional dynamics needed to interpret it. Ask whether the adopted planet also predicts the observed gap depth and whether a different architecture could match the full radial profile. Keep each interpretation next to the test that could support or reject it.
Read an arc as an observation before selecting its cause
For ARKS VI, Figure 6 separates radial regions and azimuthal profiles for HD 92945. Section 2.2 defines the image symmetry tests and their centers. Section 4.2 compares those image-domain results with visibility-model residuals. The discussion preserves geometry-dependent ambiguity, collisional possibilities, background-source checks and gas-related alternatives; the gas-rich systems are not described by the gas-free Lab.
Before using a bright arc as a density enhancement, draw your own schematic of the comparison operation. Mark the stellar center, fitted disk center, major axis, mask and restoring beam. Ask which changes would survive shifting the center within its uncertainty. Then ask whether an arc at another wavelength traces the same grain population. The next step is to test which force could make the measured asymmetry.
Use the Lab for a controlled counterfactual
The experiment supplies a narrower question than these surveys. Its conservative probe begins in a specified exterior 2:1 family and follows the critical angle over 150 planet periods. In the saved window the angle remains bounded; the same initial orbit without the planet circulates. A half-step run checks the numerical trajectory. This finite-window result is evidence for that initial state, not a proof of permanent capture or the origin of an entire observed disk.
The live multi-size cloud includes collision transfers, radiation pressure and PR, so individual daughters need not retain the parent’s resonant behavior. Change the planet only after writing a prediction: which future angles should respond, which grains can leave quickly, and which observational band should emphasize them? A slider should not be used to retrofit a visual match while its history is forgotten. Export the time of every external-driver change.
Keep the all-parent stress record nearby. It demonstrates that an apparently thin parent belt can produce a much larger radiating cross section. If collisions make an operator stiff or optical depth crosses the model boundary, report where the calculation stopped. A partial record supports conclusions only over its completed time window; long-time equilibrium requires a separate test.
Reading:
Design the next observation as a discriminating test
Choose one feature and two explanations. For example, compare a dynamical pattern tied to planetary phase with a transient local collision. Write down an observable whose future behavior differs: pattern motion, wavelength-dependent halo extent, a stable stellar offset, or a gas kinematic signature. Then state the required cadence, angular resolution and astrometric reference.
The public HD 48682 exercise helps make this concrete. Different radii and grain laws yield nearby conditional scores. Removing the image term or changing the optical law reveals which part of an apparent constraint came from an assumption. Repeat this reasoning on paper for the ARKS figure you selected. You may end with an unresolved alternative; that is a defensible reading result when the available evidence has not yet separated it.
A finished reading note should contain the exact paper version, the assigned section and figure, the observable, the forward model, the added dynamical assumption, one credible alternative and one measurement that would distinguish them. Such a note can support a research question without claiming to have reproduced a survey or discovered a planet.
Reading: