Wavelength dependence of Deneb’s variable polarization

Determine whether the variable component of Deneb’s broadband linear polarization is wavelength independent or wavelength dependent by conducting simultaneous multi-band polarimetric observations to test for phase differences or sign changes across filters, thereby discriminating between optically thin wind scattering and either optically thick wind structures or non-radial pulsations.

Background

The paper reports large-amplitude, irregular polarization variability in Deneb and considers two candidate mechanisms: scattering in a clumpy wind and non-radial pulsations. The authors note that wavelength dependence of the variable component is a key diagnostic because optically thin wind structures should produce wavelength-independent variability, whereas optically thick structures or pulsations should produce wavelength-dependent signals, potentially including phase reversals across bands.

Initial multi-band observations are sparse, and while they do not yet show the expected phase differences, the dataset is insufficient to reach a firm conclusion. Resolving the wavelength dependence would help identify the dominant polarigenic mechanism and clarify the relationship between polarization and other observed variability.