Moderate Asphericity of the SN 2002ic Circumstellar Envelope

Abstract

The polarization of SN 2002ic interacting with a dense circumstellar envelope is calculated in the context of the asymmetric version of a previously proposed spherical interaction model. The circumstellar envelope is taken to be oblate. The observed polarization (Wang et al. 2004) can be reproduced for an aspect ratio of 0.65-0.7 assuming inclination angles >60 degrees. This model predicts a weak sensitivity of the line profiles to the orientation, in agreement with the absence of significant variations of the line profiles among SN 2002ic-like supernovae. We propose a test for distinguishing between the binary and single star progenitor scenarios based upon the polarization distribution function for the growing sample of these events.