An attempt to determine the magnetic field configuration in the planetary nebula K 3-35 with ALMA

We examined dust polarisation within the planetary nebula (PN) K 3-35 using the Atacama Large Millimeter/Submillimeter Array (ALMA). This investigation aimed to identify and trace the magnetic field within the PN, as it potentially plays a crucial role in shaping this bipolar nebula. Our findings include a marginal detection of the polarised region and low fractional polarisation (peaking at 1.4%). Assuming a certain level of validity, we observed well-organised dust grains aligned along the equatorial plane of the PN, indicating a magnetic field alignment with the outflows. The limited detection of polarisation at submillimeter wavelengths in this PN and others may be attributed to a pronounced optical depth. However, our analysis of K 3-35 with the code dusty does not seem to support this idea. We also modelled the SED of K3-35, and our best-fit models included a mixture of silicates and amorphous carbon. The grains of amorphous carbon are less susceptible to alignment with the magnetic field, which could, at least partially, explain the observed low polarisation. The models presented in this article should be considered preliminary, and a more advanced approach is needed for a more complete interpretation of the results.