A Tale of Three Dust Populations: Variable R V and Extreme Polarization along Sight Lines toward ζ Ophiuchi

Dust permeates the interstellar medium, reddening and polarizing background starlight, but dust properties vary with local environment. In order to characterize in a highly irradiated diffuse cloud, we measure optical polarization towards 27 stars surrounding mid-latitude $b$=$+$24$^{\circ}$ O9.2IV star $\zeta$ Ophiuchi, using new spectroscopy polarimetry. We incrementally deredden depolarize distance, allowing us distinguish components along these sightlines. The data indicate three distinct populations: foreground component characteristic of average Milky Way ($R_{\rm{V}}$$\approx$3.1, $d$$\lesssim$180 pc), mid-distance vicinity Oph ($R_{\rm{V}}$$\approx$2.4, 200 pc$<$$d$$<$300 non-polarizing distant ($R_{\rm{V}}$$\approx$3.6, 600 pc$<$$d$$<$2000 pc). Prominent 8 $\mu$m infrared striations spanning field view likely have high Polycyclic Aromatic Hydrocarbon content are illuminated by Oph. Foreground-subtracted polarizations roughly align striations, which, argue, lie immediately behind constitute highly-polarizing dust. This polarizes very efficiently ($P_{\rm{V}}$$>$9.1$E(B-V)$), implying degree grain alignment suggesting that bulk occurs small fraction volume. large $R_{\rm{V}}$ reveals above Galactic Plane ($z$$>$250 pc) may contain greater grains than average.