Péridier Library Abstract Archive

Abstract No. UT 354

Title: Polarization of SN 1987A Revisited
Author(s): Lifan Wang, and J. Craig Wheeler Department of Astronomy, University of Texas, Austin, TX 78712
Keywords: stars: individual (SN 1987A) -- stars: supernovae
E-Mail: Lifan Wang, J. Craig Wheeler
Preprint: Document source or PostScript
Release date: 03/04/96 12:46:30
Publication status: Ap.J. Lett., in press
Comments: 7 pages, 3 figures

The conventional picture for the origin of the polarization of a supernova is based on a model of Thomson or resonance scattering of photons traveling through an aspherical supernova atmosphere. Positive detection of intrinsic polarization in SN 1987A is then interpretated as evidence of an asymmetrical supernova atmosphere. We show here a different view based on the scattering of the supernova light by a dusty circumstellar material (CSM), or the "light echo" effect. At a given epoch after the explosion, the observed photons consist of both those propagating directly from the supernova and those scattered by dust particles in the CSM. Polarized light can be produced if the distribution of the dust particles is aspherical. The model can reproduce both the time evolutionof the observed broad band polarization of SN 1987A and major features of the polarization spectra. It is also successful in providing a natural model for the early infrared light curve, in particular the observed 30 day delay of the IR maximum compared to the maximum of the bolometric light curve.