Ejecta masses in Type Ia Supernovae -- Implications for the Progenitor and the Explosion Scenario

TL;DR

This study analyzes ejecta masses of 28 Type Ia supernovae, finding most below the Chandrasekhar limit, supporting sub-Chandrasekhar explosion models, with some consistent with near-Chandrasekhar explosions, informing progenitor and explosion scenarios.

Contribution

First comprehensive analysis of ejecta masses for a sample of 28 SNe Ia, providing evidence for diverse explosion mechanisms including sub- and near-Chandrasekhar models.

Findings

Majority of SNe Ia have ejecta masses below 1.4 M$_\ m\odot$

Approximately half of the sample is compatible with both explosion models

Results support diversity in progenitor systems and explosion mechanisms

Abstract

The progenitor system(s) as well as the explosion mechanism(s) of thermonuclear (Type Ia) supernovae are long-standing issues in astrophysics. Here we present ejecta masses and other physical parameters for 28 recent Type Ia supernovae inferred from multiband photometric and optical spectroscopic data. Our results confirm that the majority of SNe Ia show {\it observable} ejecta masses below the Chandrasekhar-limit (having a mean $M_{\rm ej} \approx 1.1 \pm 0.3$ M$_\odot$), consistent with the predictions of recent sub-M$_{\rm Ch}$ explosion models. They are compatible with models assuming either single- or double-degenerate progenitor configurations. We also recover a sub-sample of supernovae within $1.2 $ M$_\odot$ $< M_{\rm {ej}} < 1.5$ M$_\odot$ that are consistent with near-Chandrasekhar explosions. Taking into account the uncertainties of the inferred ejecta masses, about half of our SNe are compatible with both explosion models. We compare our results with those in previous studies, and discuss the caveats and concerns regarding the applied methodology.