Characterizing Changes in the Be Star Population of NGC 663

Characterizing the amplitude and wavelength dependence of variations in the intrinsic polarization of classical Be stars can help inform how these circumstellar disks change over time. Since the observed polarization is a superposition of a component arising from the interstellar medium (ISP) and a component intrinsic to the Be star itself, robustly determining the ISP component is critical to isolating the intrinsic component. We present our analysis of multi-epoch, multi-wavelength photometric and polarimetric imaging of NGC 663. NGC 663 is an open cluster that is known to host a large population of Be stars. We use GAIA Data Release 2 to refine the distance and membership of NGC 663, and use these results to construct a refined field star polarization map towards the cluster, thereby enabling us to better quantify the ISP along the line of sight. This program is supported by NSF-AST 1411563, 1412110, and 1412135, along with the NSF REU program at the University of Oklahoma.