The Asymmetrical Wind of the Candidate Luminous Blue Variable MWC 314

Abstract

We present the results of long-term spectropolarimetric and spectroscopic monitoring of MWC 314, a candidate Luminous Blue Variable star. We detect the first evidence of H$α$ variability in MWC 314, and find no apparent periodicity in this emission. The total R-band polarization is observed to vary between 2.21% and 3.00% at a position angle consistently around $\sim0^{\circ}$, indicating the presence of a time-variable intrinsic polarization component, hence an asymmetrical circumstellar envelope. We find suggestive evidence that MWC 314's intrinsic polarization exhibits a wavelength-independent magnitude varying between 0.09% and 0.58% at a wavelength-independent position angle covering all four quadrants of the Stokes Q-U plane. Electron scattering off of density clumps in MWC 314's wind is considered as the probable mechanism responsible for these variations.

19 pages, 6 figures, accepted in PASP