porous particles in protoplanetary disks

[Maxim Yurkin]

Dear colleagues,

Here is another interesting paper: Vargas G., Guirado D., Carrasco-Gonzalez C., Munoz O., Yurkin M.A., Macias E.,Jaquez-Dominguez J.M., and Garcia-Izquierdo F.J. Modeling (sub-)millimeter scattering properties of fractal and consolidated porous particles: Applications to protoplanetary disks. Astrophys. J. 1004, 225 (2026). (open access)

It tackles a long-standing puzzle in protoplanetary disks, related to inconsistencies between intensity and polarization measurements (mostly because researchers have been using spheres or other simple models so far). However, I am not an expert in this topic, so I will focus on the underlying DDA simulations for porous particles, like the ones in the attached figure. Two important questions are:

- how large particles can be simulated (covering all radio wavelengths used for studying these disks)?

- how to reach good accuracy at a minimal computational cost (when orientation over both random realizations and orientation is required).

Current paper is only the first step in this direction - we have covered volume-equivalent sizes up to 1 mm (see PSCat catalog at https://zenodo.org/records/19485482) and have quantified, but not yet optimized the accuracy. However, simulations for particle sizes up to 1 cm are underway, they are expected to be much more challenging and may even hit the feasibility boundary of the DDA (although we do have a couple of tricks up our sleeves).

Maxim.