The polarization of supernova light - A measure of deviation from spherical symmetry
Abstract
The assumption of spherical symmetry, made in most theoretical models of supernova (SN) explosions, light curves, and spectra, and in attempts to use SN explosions as cosmological distance indicators, has never been justified observationally. An observational test of this assumption is suggested here, based upon the likelihood that SN atmospheres are scattering dominated and the fact that light from an unresolved, asymmetric, scattering atmosphere is linearly polarized. We have calculated the linear polarization of SN light which a nonspherical, scattering-dominated, SN atmosphere would produce as a function of its asphericity. The effect of asphericity on the inferred total luminosity of the SN has been calculated as well. We have considered Thomson scattering, resonance scattering, and a mixture of scattering and absorption. The last of these cases can yield a significantly higher degree of polarization than that expected from the classical, pure scattering atmosphere. The effects of interstellar matter on the observed SN polarization have been included. Interstellar dust not only changes the observed linear polarization but converts linearly polarized light into circularly polarized light as well, as a result of its linear birefringence. Existing, preliminary observations of supernova polarization are reviewed in the light of these results. Suggestions are made for future observation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1982
- DOI:
- 10.1086/160559
- Bibcode:
- 1982ApJ...263..902S
- Keywords:
-
- Asphericity;
- Atmospheric Scattering;
- Linear Polarization;
- Polarized Light;
- Stellar Atmospheres;
- Supernovae;
- Atmospheric Attenuation;
- Cosmic Dust;
- Electron Scattering;
- Interstellar Matter;
- Light Curve;
- Resonance Scattering;
- Astrophysics