Speaker
Description
Interpreting (sub-)millimeter observations of protoplanetary disks requires robust constraints on dust growth, yet the maximum grain size inferred from polarization often differ from those derived from continuum spectral slopes. This contribution presents numerical light-scattering calculations to assess whether particle porosity and morphology can help alleviate this discrepancy. Two dust populations are considered: consolidated porous particles computed with the discrete dipole approximation and highly porous fractal aggregates computed with the multiple-sphere T-matrix method. For both populations, scattering matrix elements, cross-sections, and effective albedo are derived for a powerlaw size distribution at ten wavelengths between 0.87 and 10 mm, adopting the DSHARP composition. We find that increasing porosity enhances forward scattering, raises the linear polarization fraction near 90°, and extends efficient polarized self-scattering to larger maximum particle sizes compare with compact spheres. Porosity also lowers the absorption mass opacity, implying larger inferred disk masses than those derived from models assuming compact spherical particles. The opacity tables and scattering-matrix elements are available in a public repository for use in models of protoplanetary disk. Future work will extend the catalog toward larger sizes and additional compositions, while a neural network approach is explored to expand the catalog from the numerical simulation data.
