# A Polarization Sequence for Type Ia Supernovae?

## TL;DR

This study analyzes polarization data of Type Ia supernovae to identify patterns that could reveal their explosion mechanisms and progenitor systems, suggesting either a bimodal polarization distribution or a polarization sequence related to spectral features.

## Contribution

It provides the first comprehensive analysis of polarization measurements in SNe Ia, proposing a polarization sequence or bimodal distribution with implications for supernova models.

## Key findings

- Polarization degree may be bimodal among SNe Ia
- Polarization of Si II absorption increases with REW
- Potential link between polarization patterns and explosion mechanisms

## Abstract

Early polarization observations on Type Ia supernovae (SNe Ia) may reveal the geometry of supernova ejecta, and then put constraints on their explosion mechanism and their progenitor model. We performed a literature search of SNe Ia with polarization measurements and determined the polarization and relative equivalent width (REW) of Si II 635.5-nm absorption feature at -5 days after the maximum light. We found that either the distribution of observed polarization degree is bimodal, i.e. the broad line SNe Ia have systematically higher polarization than all other SNe Ia, or all kind of SNe Ia share the same polarization sequence, i.e. the polarization of Si II 635.5-nm absorption feature increases with the REW. We also discussed the potential meaning of the discovery on the explosion mechanism and progenitor model of SNe Ia.