[P-CG24] New Developments of Planetary Sciences with ALMA

[PCG24-06] Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization

*Ryo Tazaki¹, Hidekazu Tanaka¹, Takayuki Muto², Akimasa Kataoka³, Satoshi Okuzumi⁴ (1.Tohoku University, 2.Kogakuin University, 3.NAOJ, 4.Tokyo Institute of Technology)

Keywords:Protoplanetary disks, Millimeter-wave polarization, Dust

Dust coagulation in protoplanetary disks is the first step of planetesimal formation and a pathway from dust aggregates to planetesimals remains unclear. Both laboratory and numerical studies have so far shown that the structure of a dust aggregate plays important roles in planetesimal formation. However, the aggregate structure has been poorly constrained by disk observations. Recently, ALMA opens a new window to observe (sub-)millimeter-wave polarization of disks, which is expected to provide additional constraints on dust aggregate properties. In this study, we perform 3D radiative transfer simulations in order to study how the structure of dust aggregates affects millimeter-wave polarization from disks. As a result, it is found that relatively compact particles are favorable to explain observed millimeter-wave scattering polarization of disks, whereas highly porous and fractal particles fail to explain the observations.