Refining Dust Properties in Protostellar Envelopes and Disks: Insights from ALMA and NOEMA Observations (PEBBLES/ENYGMA)

The evolution of astrophysical dust during early star formation is vital to understanding disk and planet formation, and magnetic fields play a role in regulating this process. Theoretical studies proposed two main mechanisms for dust polarization at (sub-)millimeter wavelengths: dust grain alignment due to the magnetic field (e.g., Lazarian et al. 2015) and self-scattering (Kataoka et al. 2015), yet differentiating between them in observations is challenging, underlining the need for more polarization data.

 IRAS 04166-2706 (K66) and IRAS 04169-2702 (K69) are Class 0/I protostars embedded in the B213 filament. These are ideal sources to study dust evolution and the role of magnetic fields, thanks to their similar ages and the shared environment with a common magnetized configuration at the filament scale. As part of PEBBLES project, Sato et al. (2026, A&A, 706, A292), using ALMA 1 mm and 3 mm polarimetric observations resolving both the protoplanetary disks and the envelopes at 25 au and 1000 au resolutions, revealed striking differences between the two sources. K66 likely exhibits hourglass-shaped B-fields at envelope scale, and both magnetically grain alignment and self-scattering could be dominant around the disk. In contrast, K69 has more compact and weaker polarized emission at all the scales, and self-scattering could be dominant in the disk. Intriguingly, we might have found self-scattering in the inner envelope of K66, implying the existence of large grains in the envelope. This supports the theoretical works proposing grain growth in the envelope (e.g., Lombart et al. 2026) and/or ejection of large grains onto the envelope by protostellar outflows (e.g., Tsukamoto et al. 2021). I will discuss the difference between K66 and K69 and dust evolution at the early star formation phase.

 Additionally, I present our recent work on a first NOEMA polarimetric survey toward ~32 Class 0 sources (ENYGMA project), providing a new statistical view of magnetized dust evolution in deeply embedded protostellar systems. As part of this, by combining NOEMA 3 mm and ALMA 0.87 mm polarization data for 10 Orion B sources, I will discuss how multi-wavelength polarization and the dust emissivity reveal dust evolution at the early stages of star formation.