Near-infrared circular polarimetry and correlation diagrams in the Orion Becklin-Neugebauer/Kleinman-low region: contribution of dichroic extinction

Abstract

We present a deep circular polarization (CP) image of the Orion Becklin-Neugebauer (BN)/Kleinman-Low (KL)nebula in the K-s band and correlations of CP, linear polarization (LP) and H-K-s color representing extinction. The CP image clearly reveals the quadrupolar structure around the massive star IRc2, rather than BN. H-K-s color is well correlated with CP. A simple relation between dichroic extinction, color excess, CP and LP is derived. The observed correlation between the Stokes parameters and the color excess agrees with the derived relation, and suggests a major contribution of dichroic extinction to the production of CP in this region, indicating the wide existence of aligned grains.