Circumstellar Material in Type Ia Supernovae via Sodium Absorption Features

TL;DR

This study investigates the circumstellar material around Type Ia supernovae using sodium absorption features, suggesting many originate from single-degenerate systems due to observed outflows.

Contribution

It provides evidence of gas outflows in Type Ia supernovae, supporting the single-degenerate progenitor model through spectroscopic analysis.

Findings

Blueshifted absorption features indicate outflows.

Many supernovae likely originate from single-degenerate systems.

Velocity structures support progenitor system models.

Abstract

Type Ia supernovae are key tools for measuring distances on a cosmic scale. They are generally thought to be the thermonuclear explosion of an accreting white dwarf in a close binary system. The nature of the mass donor is still uncertain. In the single-degenerate model it is a main-sequence star or an evolved star, whereas in the double-degenerate model it is another white dwarf. We show that the velocity structure of absorbing material along the line of sight to 35 type Ia supernovae tends to be blueshifted. These structures are likely signatures of gas outflows from the supernova progenitor systems. Thus many type Ia supernovae in nearby spiral galaxies may originate in single-degenerate systems.