and millimeter) wavelengths is due to spinning non-spherical dust grains aligned with respect to the magnetic field. However, two other polarization mechanisms have been proposed, mostly in the study of protoplanetary discs.\
First, mm-sized grains may not be aligned by the magnetic field (due to the slow Larmor precession), but rather by the radiative flux, as shown by @Tazaki2017. In this case, the polarization traces the radiation anisotropy (see figure 12 of @Tazaki2017). The application of this mechanism to our bipolar evolved nebula might produce different results due to the different physical and morphological conditions in OH231.8+4.2 compared to protoplanetary disks. However, based on the general distribution of the polarization vectors indicated by the disc model in the case of radiative polarization, we can make a first guess on whether this process could explain the polarization seen in OH 231.8+4.1. In the case of grain alignment caused by a radiative flux the polarization distribution would more likely be centro-symmetric (or spherical symmetric). The millimeter data obtained with CARMA indicates that only the $\overrightarrow{E}$-vectors located in the upper area, corresponding to the regions A and B in our new ALMA dataset, are consistent with radiative grain alignment. However, the high resolution 